docs: update client docs

README.md

···
 ```sh
 npx @hey-api/openapi-ts \
   -i https://get.heyapi.dev/hey-api/backend \
-  -o src/client \
-  -c @hey-api/client-fetch
+  -o src/client
 ```
 
 Congratulations on creating your first client! 🎉 You can learn more about the generated files on the [Output](https://heyapi.dev/openapi-ts/output) page.
-
-Before you can make API requests with the client you've just created, you need to install `@hey-api/client-fetch` and configure it.
 
 ## Installation
 
 #### npm
 
 ```sh
-npm install @hey-api/client-fetch && npm install @hey-api/openapi-ts -D
+npm install @hey-api/openapi-ts -D
 ```
 
 #### pnpm
 
 ```sh
-pnpm add @hey-api/client-fetch && pnpm add @hey-api/openapi-ts -D
+pnpm add @hey-api/openapi-ts -D
 ```
 
 #### yarn
 
 ```sh
-yarn add @hey-api/client-fetch && yarn add @hey-api/openapi-ts -D
+yarn add @hey-api/openapi-ts -D
 ```
 
 #### bun
 
 ```sh
-bun add @hey-api/client-fetch && bun add @hey-api/openapi-ts -D
+bun add @hey-api/openapi-ts -D
 ```
 
 We recommend pinning an exact version so you can safely upgrade when you're ready. This package is in [initial development](https://semver.org/spec/v0.1.0.html#spec-item-5) and its API might change before v1.
···
 createClient({
   input: 'https://get.heyapi.dev/hey-api/backend',
   output: 'src/client',
-  plugins: ['@hey-api/client-fetch'],
 });
 ```
 
···
 export default defineConfig({
   input: 'https://get.heyapi.dev/hey-api/backend',
   output: 'src/client',
-  plugins: ['@hey-api/client-fetch'],
 });
 ```
 
···
 module.exports = {
   input: 'https://get.heyapi.dev/hey-api/backend',
   output: 'src/client',
-  plugins: ['@hey-api/client-fetch'],
 };
 ```
 
···
 export default {
   input: 'https://get.heyapi.dev/hey-api/backend',
   output: 'src/client',
-  plugins: ['@hey-api/client-fetch'],
 };
 ```
 

docs/.vitepress/config/en.ts

···
                 text: 'SDK',
               },
               {
+                link: '/openapi-ts/output/client',
+                text: 'Client',
+              },
+              {
                 link: '/openapi-ts/output/json-schema',
                 text: 'JSON Schema',
               },

docs/openapi-ts/clients/axios.md

···
 
 ## Installation
 
-Start by adding `@hey-api/client-axios` to your dependencies.
-
-::: code-group
-
-```sh [npm]
-npm install @hey-api/client-axios
-```
-
-```sh [pnpm]
-pnpm add @hey-api/client-axios
-```
-
-```sh [yarn]
-yarn add @hey-api/client-axios
-```
-
-```sh [bun]
-bun add @hey-api/client-axios
-```
-
-:::
-
 In your [configuration](/openapi-ts/get-started), add `@hey-api/client-axios` to your plugins and you'll be ready to generate client artifacts. :tada:
 
 ::: code-group
···
 You can also create your own client instance. You can use it to manually send requests or point it to a different domain.
 
 ```js
-import { createClient } from '@hey-api/client-axios';
+import { createClient } from './client/client';
 
 const myClient = createClient({
   baseURL: 'https://example.com',
···
   url: '/foo/{fooId}',
 });
 console.log(url); // prints '/foo/1?bar=baz'
-```
-
-## Bundling
-
-Sometimes, you may not want to declare client packages as a dependency. This scenario is common if you're using Hey API to generate output that is repackaged and published for other consumers under your own brand. For such cases, our clients support bundling through the `client.bundle` configuration option.
-
-```js
-export default {
-  input: 'https://get.heyapi.dev/hey-api/backend',
-  output: 'src/client',
-  plugins: [
-    {
-      bundle: true, // [!code ++]
-      name: '@hey-api/client-axios',
-    },
-  ],
-};
 ```
 
 <!--@include: ../../examples.md-->

docs/openapi-ts/clients/fetch.md

···
 
 ## Installation
 
-Start by adding `@hey-api/client-fetch` to your dependencies.
-
-::: code-group
-
-```sh [npm]
-npm install @hey-api/client-fetch
-```
-
-```sh [pnpm]
-pnpm add @hey-api/client-fetch
-```
-
-```sh [yarn]
-yarn add @hey-api/client-fetch
-```
-
-```sh [bun]
-bun add @hey-api/client-fetch
-```
-
-:::
-
 In your [configuration](/openapi-ts/get-started), add `@hey-api/client-fetch` to your plugins and you'll be ready to generate client artifacts. :tada:
 
 ::: code-group
···
   -o src/client \
   -c @hey-api/client-fetch # [!code ++]
 ```
+
+:::
+
+::: tip
+
+This step is optional because Fetch is the default client.
 
 :::
 
···
 You can also create your own client instance. You can use it to manually send requests or point it to a different domain.
 
 ```js
-import { createClient } from '@hey-api/client-fetch';
+import { createClient } from './client/client';
 
 const myClient = createClient({
   baseUrl: 'https://example.com',
···
   url: '/foo/{fooId}',
 });
 console.log(url); // prints '/foo/1?bar=baz'
-```
-
-## Bundling
-
-Sometimes, you may not want to declare client packages as a dependency. This scenario is common if you're using Hey API to generate output that is repackaged and published for other consumers under your own brand. For such cases, our clients support bundling through the `client.bundle` configuration option.
-
-```js
-export default {
-  input: 'https://get.heyapi.dev/hey-api/backend',
-  output: 'src/client',
-  plugins: [
-    {
-      bundle: true, // [!code ++]
-      name: '@hey-api/client-fetch',
-    },
-  ],
-};
 ```
 
 <!--@include: ../../examples.md-->

docs/openapi-ts/clients/next-js.md

···
 
 ## Installation
 
-Start by adding `@hey-api/client-next` to your dependencies.
-
-::: code-group
-
-```sh [npm]
-npm install @hey-api/client-next
-```
-
-```sh [pnpm]
-pnpm add @hey-api/client-next
-```
-
-```sh [yarn]
-yarn add @hey-api/client-next
-```
-
-```sh [bun]
-bun add @hey-api/client-next
-```
-
-:::
-
 In your [configuration](/openapi-ts/get-started), add `@hey-api/client-next` to your plugins and you'll be ready to generate client artifacts. :tada:
 
 ::: code-group
···
 You can also create your own client instance. You can use it to manually send requests or point it to a different domain.
 
 ```js
-import { createClient } from '@hey-api/client-next';
+import { createClient } from './client/client';
 
 const myClient = createClient({
   baseUrl: 'https://example.com',
···
   url: '/foo/{fooId}',
 });
 console.log(url); // prints '/foo/1?bar=baz'
-```
-
-## Bundling
-
-Sometimes, you may not want to declare client packages as a dependency. This scenario is common if you're using Hey API to generate output that is repackaged and published for other consumers under your own brand. For such cases, our clients support bundling through the `client.bundle` configuration option.
-
-```js
-export default {
-  input: 'https://get.heyapi.dev/hey-api/backend',
-  output: 'src/client',
-  plugins: [
-    {
-      bundle: true, // [!code ++]
-      name: '@hey-api/client-next',
-    },
-  ],
-};
 ```
 
 <!--@include: ../../examples.md-->

docs/openapi-ts/configuration.md

···
 export default defineConfig({
   input: 'https://get.heyapi.dev/hey-api/backend',
   output: 'src/client',
-  plugins: ['@hey-api/client-fetch'],
 });
 ```
 
···
 module.exports = {
   input: 'https://get.heyapi.dev/hey-api/backend',
   output: 'src/client',
-  plugins: ['@hey-api/client-fetch'],
 };
 ```
 
···
 export default {
   input: 'https://get.heyapi.dev/hey-api/backend',
   output: 'src/client',
-  plugins: ['@hey-api/client-fetch'],
 };
 ```
 
···
     validate_EXPERIMENTAL: true, // [!code ++]
   },
   output: 'src/client',
-  plugins: ['@hey-api/client-fetch'],
 };
 ```
 
···
     format: false, // [!code ++]
     path: 'src/client',
   },
-  plugins: ['@hey-api/client-fetch'],
 };
 ```
 
···
     format: 'prettier', // [!code ++]
     path: 'src/client',
   },
-  plugins: ['@hey-api/client-fetch'],
 };
 ```
 
···
     format: 'biome', // [!code ++]
     path: 'src/client',
   },
-  plugins: ['@hey-api/client-fetch'],
 };
 ```
 
···
     lint: false, // [!code ++]
     path: 'src/client',
   },
-  plugins: ['@hey-api/client-fetch'],
 };
 ```
 
···
     lint: 'eslint', // [!code ++]
     path: 'src/client',
   },
-  plugins: ['@hey-api/client-fetch'],
 };
 ```
 
···
     lint: 'biome', // [!code ++]
     path: 'src/client',
   },
-  plugins: ['@hey-api/client-fetch'],
 };
 ```
 
···
     lint: 'oxlint', // [!code ++]
     path: 'src/client',
   },
-  plugins: ['@hey-api/client-fetch'],
 };
 ```
 
···
     path: 'https://get.heyapi.dev/hey-api/backend',
   },
   output: 'src/client',
-  plugins: ['@hey-api/client-fetch'],
 };
 ```
 
···
     path: 'https://get.heyapi.dev/hey-api/backend',
   },
   output: 'src/client',
-  plugins: ['@hey-api/client-fetch'],
 };
 ```
 
···
     path: 'https://get.heyapi.dev/hey-api/backend',
   },
   output: 'src/client',
-  plugins: ['@hey-api/client-fetch'],
 };
 ```
 
···
     path: 'https://get.heyapi.dev/hey-api/backend',
   },
   output: 'src/client',
-  plugins: ['@hey-api/client-fetch'],
 };
 ```
 
···
     path: 'https://get.heyapi.dev/hey-api/backend',
   },
   output: 'src/client',
-  plugins: ['@hey-api/client-fetch'],
 };
 ```
 
···
     path: 'https://get.heyapi.dev/hey-api/backend',
   },
   output: 'src/client',
-  plugins: ['@hey-api/client-fetch'],
 };
 ```
 
···
     path: 'https://get.heyapi.dev/hey-api/backend',
   },
   output: 'src/client',
-  plugins: ['@hey-api/client-fetch'],
 };
 ```
 
···
     path: 'https://get.heyapi.dev/hey-api/backend',
   },
   output: 'src/client',
-  plugins: ['@hey-api/client-fetch'],
 };
 ```
 
···
     path: 'https://get.heyapi.dev/hey-api/backend',
   },
   output: 'src/client',
-  plugins: ['@hey-api/client-fetch'],
 };
 ```
 
···
     path: 'https://get.heyapi.dev/hey-api/backend',
   },
   output: 'src/client',
-  plugins: ['@hey-api/client-fetch'],
 };
 ```
 
···
     path: 'https://get.heyapi.dev/hey-api/backend',
   },
   output: 'src/client',
-  plugins: ['@hey-api/client-fetch'],
 };
 ```
 
···
     path: 'https://get.heyapi.dev/hey-api/backend',
   },
   output: 'src/client',
-  plugins: ['@hey-api/client-fetch'],
 };
 ```
 
···
     path: 'https://get.heyapi.dev/hey-api/backend',
   },
   output: 'src/client',
-  plugins: ['@hey-api/client-fetch'],
 };
 ```
 
···
     path: 'https://get.heyapi.dev/hey-api/backend',
   },
   output: 'src/client',
-  plugins: ['@hey-api/client-fetch'],
 };
 ```
 
···
     path: 'https://get.heyapi.dev/hey-api/backend',
   },
   output: 'src/client',
-  plugins: ['@hey-api/client-fetch'],
 };
 ```
 
···
     path: 'https://get.heyapi.dev/hey-api/backend',
   },
   output: 'src/client',
-  plugins: ['@hey-api/client-fetch'],
 };
 ```
 
···
     path: 'https://get.heyapi.dev/hey-api/backend',
   },
   output: 'src/client',
-  plugins: ['@hey-api/client-fetch'],
 };
 ```
 
···
     watch: true, // [!code ++]
   },
   output: 'src/client',
-  plugins: ['@hey-api/client-fetch'],
 };
 ```
 
···
 npx @hey-api/openapi-ts \
   -i https://get.heyapi.dev/hey-api/backend \
   -o src/client \
-  -c @hey-api/client-fetch \
   -w  # [!code ++]
 ```
 
···
     clean: false, // [!code ++]
     path: 'src/client',
   },
-  plugins: ['@hey-api/client-fetch'],
 };
 ```
 

docs/openapi-ts/get-started.md

···
 ```sh
 npx @hey-api/openapi-ts \
   -i https://get.heyapi.dev/hey-api/backend \
-  -o src/client \
-  -c @hey-api/client-fetch
+  -o src/client
 ```
 
 Congratulations on creating your first client! 🎉 You can learn more about the generated files on the [Output](/openapi-ts/output) page.
 
-Before you can make API requests with the client you've just created, you need to install `@hey-api/client-fetch` and configure it. Let's start by declaring your dependencies.
-
 ## Installation
 
 ::: code-group
 
 ```sh [npm]
-npm install @hey-api/client-fetch && npm install @hey-api/openapi-ts -D
+npm install @hey-api/openapi-ts -D
 ```
 
 ```sh [pnpm]
-pnpm add @hey-api/client-fetch && pnpm add @hey-api/openapi-ts -D
+pnpm add @hey-api/openapi-ts -D
 ```
 
 ```sh [yarn]
-yarn add @hey-api/client-fetch && yarn add @hey-api/openapi-ts -D
+yarn add @hey-api/openapi-ts -D
 ```
 
 ```sh [bun]
-bun add @hey-api/client-fetch && bun add @hey-api/openapi-ts -D
+bun add @hey-api/openapi-ts -D
 ```
 
 :::
···
 createClient({
   input: 'https://get.heyapi.dev/hey-api/backend',
   output: 'src/client',
-  plugins: ['@hey-api/client-fetch'],
 });
 ```
 

docs/openapi-ts/integrations.md

···
 ```sh [Hey API]
 npx @hey-api/openapi-ts \
   -i https://get.heyapi.dev/hey-api/backend \
-  -o src/client \
-  -c @hey-api/client-fetch
+  -o src/client
 ```
 
 ```sh [OpenAPI TypeScript]

docs/openapi-ts/output.md

···
 ├── node_modules/
 ├── src/
 │ ├── client/
+│ │ ├── client/
+│ │ ├── core/
 │ │ ├── client.gen.ts
 │ │ ├── index.ts
 │ │ ├── sdk.gen.ts
···
     indexFile: false, // [!code ++]
     path: 'src/client',
   },
-  plugins: ['@hey-api/client-fetch'],
 };
 ```
 
···
   output: 'src/client',
   plugins: [
     ...defaultPlugins,
-    '@hey-api/client-fetch',
     {
       exportFromIndex: true, // [!code ++]
       name: 'zod',
···
 ::: warning
 Re-exporting additional files from index file may result in broken output due to naming conflicts.
 :::
-
-## Client
-
-`client.gen.ts` is generated by [client plugins](/openapi-ts/clients). If you choose to generate SDKs (enabled by default), you must specify a client which will create this file.
-
-::: code-group
-
-```ts [client.gen.ts]
-import { createClient, createConfig } from '@hey-api/client-fetch';
-
-export const client = createClient(createConfig());
-```
-
-:::
-
-The contents of this file are consumed by SDKs, but you can also import `client` in your application to perform additional configuration or send manual requests.
 
 <!--@include: ../examples.md-->
 <!--@include: ../sponsors.md-->

docs/openapi-ts/output/client.md

···
+---
+title: Client
+description: Learn about files generated with @hey-api/openapi-ts.
+---
+
+# Client
+
+`client.gen.ts` is generated by [client plugins](/openapi-ts/clients). If you choose to generate SDKs (enabled by default), we use the Fetch client unless specified otherwise.
+
+::: code-group
+
+```ts [client.gen.ts]
+import { createClient, createConfig } from './client';
+
+export const client = createClient(createConfig());
+```
+
+:::
+
+The contents of this file are consumed by SDKs, but you can also import `client` in your application to perform additional configuration or send manual requests.
+
+## Bundle
+
+Client plugins provide their bundles inside `client` and `core` folders. The contents of these folders don't depend on the provided input. Everything inside these folders serves as a scaffolding so the generated code can make HTTP requests.
+
+<!--@include: ../../examples.md-->
+<!--@include: ../../sponsors.md-->

docs/openapi-ts/output/json-schema.md

···
   output: 'src/client',
   plugins: [
     ...defaultPlugins,
-    '@hey-api/client-fetch',
     {
       name: '@hey-api/schemas',
       type: 'json', // [!code ++]
···
   output: 'src/client',
   plugins: [
     ...defaultPlugins,
-    '@hey-api/client-fetch',
     {
       name: '@hey-api/schemas',
       type: 'form', // [!code ++]
···
   output: 'src/client',
   plugins: [
     ...defaultPlugins,
-    '@hey-api/client-fetch',
     '@hey-api/schemas', // [!code --]
   ],
 };

docs/openapi-ts/output/sdk.md

···
   output: 'src/client',
   plugins: [
     ...defaultPlugins,
-    '@hey-api/client-fetch',
     {
       asClass: false, // default // [!code ++]
       name: '@hey-api/sdk',
···
   output: 'src/client',
   plugins: [
     ...defaultPlugins,
-    '@hey-api/client-fetch',
     {
       asClass: true, // [!code ++]
       name: '@hey-api/sdk',
···
   input: 'https://get.heyapi.dev/hey-api/backend',
   output: 'src/client',
   plugins: [
-    '@hey-api/client-fetch',
     '@hey-api/typescript',
     '@hey-api/sdk', // [!code --]
   ],
···
 ::: code-group
 
 ```ts [flat]
-import type { Options } from '@hey-api/client-fetch';
-
+import type { Options } from './client';
 import { client as _heyApiClient } from './client.gen';
 import type { AddPetData, AddPetError, AddPetResponse } from './types.gen';
 
···
 ```
 
 ```ts [class]
-import type { Options } from '@hey-api/client-fetch';
-
+import type { Options } from './client';
 import { client as _heyApiClient } from './client.gen';
 import type { AddPetData, AddPetError, AddPetResponse } from './types.gen';
 
···
 ```
 
 ```ts [none]
-import { client } from '@hey-api/client-fetch';
+import { client } from './client/client';
 
 client.post({
   body: {

docs/openapi-ts/output/typescript.md

···
 
 :::
 
-As you can see, everything is exported from `types.gen.ts`. You can import individual exports in your application and use them as necessary.
+Every generated interface inside `types.gen.ts` is exported. You can import individual exports in your application and use them as necessary.
 
 ## Configuration
 
···
   output: 'src/client',
   plugins: [
     ...defaultPlugins,
-    '@hey-api/client-fetch',
     {
       name: '@hey-api/typescript',
       // ...custom options // [!code ++]
···
   output: 'src/client',
   plugins: [
     ...defaultPlugins,
-    '@hey-api/client-fetch',
     {
       enums: false, // default // [!code ++]
       name: '@hey-api/typescript',
···
   output: 'src/client',
   plugins: [
     ...defaultPlugins,
-    '@hey-api/client-fetch',
     {
       enums: 'javascript', // [!code ++]
       name: '@hey-api/typescript',
···
   output: 'src/client',
   plugins: [
     ...defaultPlugins,
-    '@hey-api/client-fetch',
     {
       enums: 'typescript', // [!code ++]
       name: '@hey-api/typescript',

docs/openapi-ts/plugins/custom.md

···
   input: 'https://get.heyapi.dev/hey-api/backend',
   output: 'src/client',
   plugins: [
-    '@hey-api/client-fetch',
     defineConfig({
       myOption: true,
     }),

docs/openapi-ts/plugins/fastify.md

···
   output: 'src/client',
   plugins: [
     ...defaultPlugins,
-    '@hey-api/client-fetch',
     'fastify', // [!code ++]
   ],
 };

docs/openapi-ts/plugins/tanstack-query.md

···
   output: 'src/client',
   plugins: [
     ...defaultPlugins,
-    '@hey-api/client-fetch',
     '@tanstack/react-query', // [!code ++]
   ],
 };
···
   output: 'src/client',
   plugins: [
     ...defaultPlugins,
-    '@hey-api/client-fetch',
     '@tanstack/vue-query', // [!code ++]
   ],
 };
···
   output: 'src/client',
   plugins: [
     ...defaultPlugins,
-    '@hey-api/client-fetch',
     '@tanstack/angular-query-experimental', // [!code ++]
   ],
 };
···
   output: 'src/client',
   plugins: [
     ...defaultPlugins,
-    '@hey-api/client-fetch',
     '@tanstack/svelte-query', // [!code ++]
   ],
 };
···
   output: 'src/client',
   plugins: [
     ...defaultPlugins,
-    '@hey-api/client-fetch',
     '@tanstack/solid-query', // [!code ++]
   ],
 };

docs/openapi-ts/plugins/valibot.md

···
   output: 'src/client',
   plugins: [
     ...defaultPlugins,
-    '@hey-api/client-fetch',
     'valibot', // [!code ++]
   ],
 };
···
   output: 'src/client',
   plugins: [
     ...defaultPlugins,
-    '@hey-api/client-fetch',
     'valibot',
     {
       name: '@hey-api/sdk', // [!code ++]

docs/openapi-ts/plugins/zod.md

···
   output: 'src/client',
   plugins: [
     // ...other plugins
-    '@hey-api/client-fetch',
     'zod', // [!code ++]
   ],
 };
···
   output: 'src/client',
   plugins: [
     // ...other plugins
-    '@hey-api/client-fetch',
     'zod',
     {
       name: '@hey-api/sdk', // [!code ++]

docs/openapi-ts/transformers.md

···
   output: 'src/client',
   plugins: [
     ...defaultPlugins,
-    '@hey-api/client-fetch',
     '@hey-api/transformers', // [!code ++]
   ],
 };
···
   output: 'src/client',
   plugins: [
     ...defaultPlugins,
-    '@hey-api/client-fetch',
     '@hey-api/transformers',
     {
       name: '@hey-api/sdk', // [!code ++]
···
   output: 'src/client',
   plugins: [
     ...defaultPlugins,
-    '@hey-api/client-fetch',
     {
       dates: true, // [!code ++]
       name: '@hey-api/transformers',

docs/openapi-ts/validators.md

···
   input: 'https://get.heyapi.dev/hey-api/backend',
   output: 'src/client',
   plugins: [
-    '@hey-api/client-fetch',
     {
       name: '@hey-api/sdk',
       validator: 'zod', // [!code ++]
···
   input: 'https://get.heyapi.dev/hey-api/backend',
   output: 'src/client',
   plugins: [
-    '@hey-api/client-fetch',
     {
       name: '@hey-api/sdk',
       validator: true, // [!code ++]

examples/openapi-ts-axios/package.json

···
     "typecheck": "tsc --noEmit"
   },
   "dependencies": {
-    "@hey-api/client-axios": "workspace:*",
     "@radix-ui/react-form": "0.1.1",
     "@radix-ui/react-icons": "1.3.2",
     "@radix-ui/themes": "3.1.6",

examples/openapi-ts-axios/src/App.tsx

···
 import './App.css';
 
-import { createClient } from '@hey-api/client-axios';
 import * as Form from '@radix-ui/react-form';
 import { DownloadIcon, PlusIcon, ReloadIcon } from '@radix-ui/react-icons';
 import {
···
 } from '@radix-ui/themes';
 import { useState } from 'react';
 
+import { createClient } from './client/client';
 import { PetSchema } from './client/schemas.gen';
 import { addPet, getPetById, updatePet } from './client/sdk.gen';
 import type { Pet } from './client/types.gen';

examples/openapi-ts-axios/src/client/client.gen.ts

···
   type Config,
   createClient,
   createConfig,
-} from '@hey-api/client-axios';
-
+} from './client';
 import type { ClientOptions } from './types.gen';
 
 /**

examples/openapi-ts-axios/src/client/client/client.ts

···
+import type { AxiosError, RawAxiosRequestHeaders } from 'axios';
+import axios from 'axios';
+
+import type { Client, Config } from './types';
+import {
+  buildUrl,
+  createConfig,
+  mergeConfigs,
+  mergeHeaders,
+  setAuthParams,
+} from './utils';
+
+export const createClient = (config: Config = {}): Client => {
+  let _config = mergeConfigs(createConfig(), config);
+
+  // eslint-disable-next-line @typescript-eslint/no-unused-vars
+  const { auth, ...configWithoutAuth } = _config;
+  const instance = axios.create(configWithoutAuth);
+
+  const getConfig = (): Config => ({ ..._config });
+
+  const setConfig = (config: Config): Config => {
+    _config = mergeConfigs(_config, config);
+    instance.defaults = {
+      ...instance.defaults,
+      ..._config,
+      // @ts-expect-error
+      headers: mergeHeaders(instance.defaults.headers, _config.headers),
+    };
+    return getConfig();
+  };
+
+  // @ts-expect-error
+  const request: Client['request'] = async (options) => {
+    const opts = {
+      ..._config,
+      ...options,
+      axios: options.axios ?? _config.axios ?? instance,
+      headers: mergeHeaders(_config.headers, options.headers),
+    };
+
+    if (opts.security) {
+      await setAuthParams({
+        ...opts,
+        security: opts.security,
+      });
+    }
+
+    if (opts.body && opts.bodySerializer) {
+      opts.body = opts.bodySerializer(opts.body);
+    }
+
+    const url = buildUrl(opts);
+
+    try {
+      // assign Axios here for consistency with fetch
+      const _axios = opts.axios!;
+      // eslint-disable-next-line @typescript-eslint/no-unused-vars
+      const { auth, ...optsWithoutAuth } = opts;
+      const response = await _axios({
+        ...optsWithoutAuth,
+        baseURL: opts.baseURL as string,
+        data: opts.body,
+        headers: opts.headers as RawAxiosRequestHeaders,
+        // let `paramsSerializer()` handle query params if it exists
+        params: opts.paramsSerializer ? opts.query : undefined,
+        url,
+      });
+
+      let { data } = response;
+
+      if (opts.responseType === 'json') {
+        if (opts.responseValidator) {
+          await opts.responseValidator(data);
+        }
+
+        if (opts.responseTransformer) {
+          data = await opts.responseTransformer(data);
+        }
+      }
+
+      return {
+        ...response,
+        data: data ?? {},
+      };
+    } catch (error) {
+      const e = error as AxiosError;
+      if (opts.throwOnError) {
+        throw e;
+      }
+      // @ts-expect-error
+      e.error = e.response?.data ?? {};
+      return e;
+    }
+  };
+
+  return {
+    buildUrl,
+    delete: (options) => request({ ...options, method: 'DELETE' }),
+    get: (options) => request({ ...options, method: 'GET' }),
+    getConfig,
+    head: (options) => request({ ...options, method: 'HEAD' }),
+    instance,
+    options: (options) => request({ ...options, method: 'OPTIONS' }),
+    patch: (options) => request({ ...options, method: 'PATCH' }),
+    post: (options) => request({ ...options, method: 'POST' }),
+    put: (options) => request({ ...options, method: 'PUT' }),
+    request,
+    setConfig,
+  } as Client;
+};

examples/openapi-ts-axios/src/client/client/index.ts

···
+export type { Auth } from '../core/auth';
+export type { QuerySerializerOptions } from '../core/bodySerializer';
+export {
+  formDataBodySerializer,
+  jsonBodySerializer,
+  urlSearchParamsBodySerializer,
+} from '../core/bodySerializer';
+export { buildClientParams } from '../core/params';
+export { createClient } from './client';
+export type {
+  Client,
+  ClientOptions,
+  Config,
+  CreateClientConfig,
+  Options,
+  OptionsLegacyParser,
+  RequestOptions,
+  RequestResult,
+  TDataShape,
+} from './types';
+export { createConfig } from './utils';

examples/openapi-ts-axios/src/client/client/types.ts

···
+import type {
+  AxiosError,
+  AxiosInstance,
+  AxiosResponse,
+  AxiosStatic,
+  CreateAxiosDefaults,
+} from 'axios';
+
+import type { Auth } from '../core/auth';
+import type { Client as CoreClient, Config as CoreConfig } from '../core/types';
+
+export interface Config<T extends ClientOptions = ClientOptions>
+  extends Omit<CreateAxiosDefaults, 'auth' | 'baseURL' | 'headers' | 'method'>,
+    CoreConfig {
+  /**
+   * Axios implementation. You can use this option to provide a custom
+   * Axios instance.
+   *
+   * @default axios
+   */
+  axios?: AxiosStatic;
+  /**
+   * Base URL for all requests made by this client.
+   */
+  baseURL?: T['baseURL'];
+  /**
+   * An object containing any HTTP headers that you want to pre-populate your
+   * `Headers` object with.
+   *
+   * {@link https://developer.mozilla.org/docs/Web/API/Headers/Headers#init See more}
+   */
+  headers?:
+    | CreateAxiosDefaults['headers']
+    | Record<
+        string,
+        | string
+        | number
+        | boolean
+        | (string | number | boolean)[]
+        | null
+        | undefined
+        | unknown
+      >;
+  /**
+   * Throw an error instead of returning it in the response?
+   *
+   * @default false
+   */
+  throwOnError?: T['throwOnError'];
+}
+
+export interface RequestOptions<
+  ThrowOnError extends boolean = boolean,
+  Url extends string = string,
+> extends Config<{
+    throwOnError: ThrowOnError;
+  }> {
+  /**
+   * Any body that you want to add to your request.
+   *
+   * {@link https://developer.mozilla.org/docs/Web/API/fetch#body}
+   */
+  body?: unknown;
+  path?: Record<string, unknown>;
+  query?: Record<string, unknown>;
+  /**
+   * Security mechanism(s) to use for the request.
+   */
+  security?: ReadonlyArray<Auth>;
+  url: Url;
+}
+
+export type RequestResult<
+  TData = unknown,
+  TError = unknown,
+  ThrowOnError extends boolean = boolean,
+> = ThrowOnError extends true
+  ? Promise<
+      AxiosResponse<
+        TData extends Record<string, unknown> ? TData[keyof TData] : TData
+      >
+    >
+  : Promise<
+      | (AxiosResponse<
+          TData extends Record<string, unknown> ? TData[keyof TData] : TData
+        > & { error: undefined })
+      | (AxiosError<
+          TError extends Record<string, unknown> ? TError[keyof TError] : TError
+        > & {
+          data: undefined;
+          error: TError extends Record<string, unknown>
+            ? TError[keyof TError]
+            : TError;
+        })
+    >;
+
+export interface ClientOptions {
+  baseURL?: string;
+  throwOnError?: boolean;
+}
+
+type MethodFn = <
+  TData = unknown,
+  TError = unknown,
+  ThrowOnError extends boolean = false,
+>(
+  options: Omit<RequestOptions<ThrowOnError>, 'method'>,
+) => RequestResult<TData, TError, ThrowOnError>;
+
+type RequestFn = <
+  TData = unknown,
+  TError = unknown,
+  ThrowOnError extends boolean = false,
+>(
+  options: Omit<RequestOptions<ThrowOnError>, 'method'> &
+    Pick<Required<RequestOptions<ThrowOnError>>, 'method'>,
+) => RequestResult<TData, TError, ThrowOnError>;
+
+type BuildUrlFn = <
+  TData extends {
+    body?: unknown;
+    path?: Record<string, unknown>;
+    query?: Record<string, unknown>;
+    url: string;
+  },
+>(
+  options: Pick<TData, 'url'> & Omit<Options<TData>, 'axios'>,
+) => string;
+
+export type Client = CoreClient<RequestFn, Config, MethodFn, BuildUrlFn> & {
+  instance: AxiosInstance;
+};
+
+/**
+ * The `createClientConfig()` function will be called on client initialization
+ * and the returned object will become the client's initial configuration.
+ *
+ * You may want to initialize your client this way instead of calling
+ * `setConfig()`. This is useful for example if you're using Next.js
+ * to ensure your client always has the correct values.
+ */
+export type CreateClientConfig<T extends ClientOptions = ClientOptions> = (
+  override?: Config<ClientOptions & T>,
+) => Config<Required<ClientOptions> & T>;
+
+export interface TDataShape {
+  body?: unknown;
+  headers?: unknown;
+  path?: unknown;
+  query?: unknown;
+  url: string;
+}
+
+type OmitKeys<T, K> = Pick<T, Exclude<keyof T, K>>;
+
+export type Options<
+  TData extends TDataShape = TDataShape,
+  ThrowOnError extends boolean = boolean,
+> = OmitKeys<RequestOptions<ThrowOnError>, 'body' | 'path' | 'query' | 'url'> &
+  Omit<TData, 'url'>;
+
+export type OptionsLegacyParser<
+  TData = unknown,
+  ThrowOnError extends boolean = boolean,
+> = TData extends { body?: any }
+  ? TData extends { headers?: any }
+    ? OmitKeys<RequestOptions<ThrowOnError>, 'body' | 'headers' | 'url'> & TData
+    : OmitKeys<RequestOptions<ThrowOnError>, 'body' | 'url'> &
+        TData &
+        Pick<RequestOptions<ThrowOnError>, 'headers'>
+  : TData extends { headers?: any }
+    ? OmitKeys<RequestOptions<ThrowOnError>, 'headers' | 'url'> &
+        TData &
+        Pick<RequestOptions<ThrowOnError>, 'body'>
+    : OmitKeys<RequestOptions<ThrowOnError>, 'url'> & TData;

examples/openapi-ts-axios/src/client/client/utils.ts

···
+import { getAuthToken } from '../core/auth';
+import type {
+  QuerySerializer,
+  QuerySerializerOptions,
+} from '../core/bodySerializer';
+import type { ArraySeparatorStyle } from '../core/pathSerializer';
+import {
+  serializeArrayParam,
+  serializeObjectParam,
+  serializePrimitiveParam,
+} from '../core/pathSerializer';
+import type { Client, ClientOptions, Config, RequestOptions } from './types';
+
+interface PathSerializer {
+  path: Record<string, unknown>;
+  url: string;
+}
+
+const PATH_PARAM_RE = /\{[^{}]+\}/g;
+
+const defaultPathSerializer = ({ path, url: _url }: PathSerializer) => {
+  let url = _url;
+  const matches = _url.match(PATH_PARAM_RE);
+  if (matches) {
+    for (const match of matches) {
+      let explode = false;
+      let name = match.substring(1, match.length - 1);
+      let style: ArraySeparatorStyle = 'simple';
+
+      if (name.endsWith('*')) {
+        explode = true;
+        name = name.substring(0, name.length - 1);
+      }
+
+      if (name.startsWith('.')) {
+        name = name.substring(1);
+        style = 'label';
+      } else if (name.startsWith(';')) {
+        name = name.substring(1);
+        style = 'matrix';
+      }
+
+      const value = path[name];
+
+      if (value === undefined || value === null) {
+        continue;
+      }
+
+      if (Array.isArray(value)) {
+        url = url.replace(
+          match,
+          serializeArrayParam({ explode, name, style, value }),
+        );
+        continue;
+      }
+
+      if (typeof value === 'object') {
+        url = url.replace(
+          match,
+          serializeObjectParam({
+            explode,
+            name,
+            style,
+            value: value as Record<string, unknown>,
+            valueOnly: true,
+          }),
+        );
+        continue;
+      }
+
+      if (style === 'matrix') {
+        url = url.replace(
+          match,
+          `;${serializePrimitiveParam({
+            name,
+            value: value as string,
+          })}`,
+        );
+        continue;
+      }
+
+      const replaceValue = encodeURIComponent(
+        style === 'label' ? `.${value as string}` : (value as string),
+      );
+      url = url.replace(match, replaceValue);
+    }
+  }
+  return url;
+};
+
+export const createQuerySerializer = <T = unknown>({
+  allowReserved,
+  array,
+  object,
+}: QuerySerializerOptions = {}) => {
+  const querySerializer = (queryParams: T) => {
+    const search: string[] = [];
+    if (queryParams && typeof queryParams === 'object') {
+      for (const name in queryParams) {
+        const value = queryParams[name];
+
+        if (value === undefined || value === null) {
+          continue;
+        }
+
+        if (Array.isArray(value)) {
+          const serializedArray = serializeArrayParam({
+            allowReserved,
+            explode: true,
+            name,
+            style: 'form',
+            value,
+            ...array,
+          });
+          if (serializedArray) search.push(serializedArray);
+        } else if (typeof value === 'object') {
+          const serializedObject = serializeObjectParam({
+            allowReserved,
+            explode: true,
+            name,
+            style: 'deepObject',
+            value: value as Record<string, unknown>,
+            ...object,
+          });
+          if (serializedObject) search.push(serializedObject);
+        } else {
+          const serializedPrimitive = serializePrimitiveParam({
+            allowReserved,
+            name,
+            value: value as string,
+          });
+          if (serializedPrimitive) search.push(serializedPrimitive);
+        }
+      }
+    }
+    return search.join('&');
+  };
+  return querySerializer;
+};
+
+export const setAuthParams = async ({
+  security,
+  ...options
+}: Pick<Required<RequestOptions>, 'security'> &
+  Pick<RequestOptions, 'auth' | 'query'> & {
+    headers: Record<any, unknown>;
+  }) => {
+  for (const auth of security) {
+    const token = await getAuthToken(auth, options.auth);
+
+    if (!token) {
+      continue;
+    }
+
+    const name = auth.name ?? 'Authorization';
+
+    switch (auth.in) {
+      case 'query':
+        if (!options.query) {
+          options.query = {};
+        }
+        options.query[name] = token;
+        break;
+      case 'cookie': {
+        const value = `${name}=${token}`;
+        if ('Cookie' in options.headers && options.headers['Cookie']) {
+          options.headers['Cookie'] = `${options.headers['Cookie']}; ${value}`;
+        } else {
+          options.headers['Cookie'] = value;
+        }
+        break;
+      }
+      case 'header':
+      default:
+        options.headers[name] = token;
+        break;
+    }
+
+    return;
+  }
+};
+
+export const buildUrl: Client['buildUrl'] = (options) => {
+  const url = getUrl({
+    path: options.path,
+    // let `paramsSerializer()` handle query params if it exists
+    query: !options.paramsSerializer ? options.query : undefined,
+    querySerializer:
+      typeof options.querySerializer === 'function'
+        ? options.querySerializer
+        : createQuerySerializer(options.querySerializer),
+    url: options.url,
+  });
+  return url;
+};
+
+export const getUrl = ({
+  path,
+  query,
+  querySerializer,
+  url: _url,
+}: {
+  path?: Record<string, unknown>;
+  query?: Record<string, unknown>;
+  querySerializer: QuerySerializer;
+  url: string;
+}) => {
+  const pathUrl = _url.startsWith('/') ? _url : `/${_url}`;
+  let url = pathUrl;
+  if (path) {
+    url = defaultPathSerializer({ path, url });
+  }
+  let search = query ? querySerializer(query) : '';
+  if (search.startsWith('?')) {
+    search = search.substring(1);
+  }
+  if (search) {
+    url += `?${search}`;
+  }
+  return url;
+};
+
+export const mergeConfigs = (a: Config, b: Config): Config => {
+  const config = { ...a, ...b };
+  config.headers = mergeHeaders(a.headers, b.headers);
+  return config;
+};
+
+/**
+ * Special Axios headers keywords allowing to set headers by request method.
+ */
+export const axiosHeadersKeywords = [
+  'common',
+  'delete',
+  'get',
+  'head',
+  'patch',
+  'post',
+  'put',
+] as const;
+
+export const mergeHeaders = (
+  ...headers: Array<Required<Config>['headers'] | undefined>
+): Record<any, unknown> => {
+  const mergedHeaders: Record<any, unknown> = {};
+  for (const header of headers) {
+    if (!header || typeof header !== 'object') {
+      continue;
+    }
+
+    const iterator = Object.entries(header);
+
+    for (const [key, value] of iterator) {
+      if (
+        axiosHeadersKeywords.includes(
+          key as (typeof axiosHeadersKeywords)[number],
+        ) &&
+        typeof value === 'object'
+      ) {
+        mergedHeaders[key] = {
+          ...(mergedHeaders[key] as Record<any, unknown>),
+          ...value,
+        };
+      } else if (value === null) {
+        delete mergedHeaders[key];
+      } else if (Array.isArray(value)) {
+        for (const v of value) {
+          // @ts-expect-error
+          mergedHeaders[key] = [...(mergedHeaders[key] ?? []), v as string];
+        }
+      } else if (value !== undefined) {
+        // assume object headers are meant to be JSON stringified, i.e. their
+        // content value in OpenAPI specification is 'application/json'
+        mergedHeaders[key] =
+          typeof value === 'object' ? JSON.stringify(value) : (value as string);
+      }
+    }
+  }
+  return mergedHeaders;
+};
+
+export const createConfig = <T extends ClientOptions = ClientOptions>(
+  override: Config<Omit<ClientOptions, keyof T> & T> = {},
+): Config<Omit<ClientOptions, keyof T> & T> => ({
+  ...override,
+});

examples/openapi-ts-axios/src/client/core/auth.ts

···
+export type AuthToken = string | undefined;
+
+export interface Auth {
+  /**
+   * Which part of the request do we use to send the auth?
+   *
+   * @default 'header'
+   */
+  in?: 'header' | 'query' | 'cookie';
+  /**
+   * Header or query parameter name.
+   *
+   * @default 'Authorization'
+   */
+  name?: string;
+  scheme?: 'basic' | 'bearer';
+  type: 'apiKey' | 'http';
+}
+
+export const getAuthToken = async (
+  auth: Auth,
+  callback: ((auth: Auth) => Promise<AuthToken> | AuthToken) | AuthToken,
+): Promise<string | undefined> => {
+  const token =
+    typeof callback === 'function' ? await callback(auth) : callback;
+
+  if (!token) {
+    return;
+  }
+
+  if (auth.scheme === 'bearer') {
+    return `Bearer ${token}`;
+  }
+
+  if (auth.scheme === 'basic') {
+    return `Basic ${btoa(token)}`;
+  }
+
+  return token;
+};

examples/openapi-ts-axios/src/client/core/bodySerializer.ts

···
+import type {
+  ArrayStyle,
+  ObjectStyle,
+  SerializerOptions,
+} from './pathSerializer';
+
+export type QuerySerializer = (query: Record<string, unknown>) => string;
+
+export type BodySerializer = (body: any) => any;
+
+export interface QuerySerializerOptions {
+  allowReserved?: boolean;
+  array?: SerializerOptions<ArrayStyle>;
+  object?: SerializerOptions<ObjectStyle>;
+}
+
+const serializeFormDataPair = (data: FormData, key: string, value: unknown) => {
+  if (typeof value === 'string' || value instanceof Blob) {
+    data.append(key, value);
+  } else {
+    data.append(key, JSON.stringify(value));
+  }
+};
+
+const serializeUrlSearchParamsPair = (
+  data: URLSearchParams,
+  key: string,
+  value: unknown,
+) => {
+  if (typeof value === 'string') {
+    data.append(key, value);
+  } else {
+    data.append(key, JSON.stringify(value));
+  }
+};
+
+export const formDataBodySerializer = {
+  bodySerializer: <T extends Record<string, any> | Array<Record<string, any>>>(
+    body: T,
+  ) => {
+    const data = new FormData();
+
+    Object.entries(body).forEach(([key, value]) => {
+      if (value === undefined || value === null) {
+        return;
+      }
+      if (Array.isArray(value)) {
+        value.forEach((v) => serializeFormDataPair(data, key, v));
+      } else {
+        serializeFormDataPair(data, key, value);
+      }
+    });
+
+    return data;
+  },
+};
+
+export const jsonBodySerializer = {
+  bodySerializer: <T>(body: T) =>
+    JSON.stringify(body, (key, value) =>
+      typeof value === 'bigint' ? value.toString() : value,
+    ),
+};
+
+export const urlSearchParamsBodySerializer = {
+  bodySerializer: <T extends Record<string, any> | Array<Record<string, any>>>(
+    body: T,
+  ) => {
+    const data = new URLSearchParams();
+
+    Object.entries(body).forEach(([key, value]) => {
+      if (value === undefined || value === null) {
+        return;
+      }
+      if (Array.isArray(value)) {
+        value.forEach((v) => serializeUrlSearchParamsPair(data, key, v));
+      } else {
+        serializeUrlSearchParamsPair(data, key, value);
+      }
+    });
+
+    return data.toString();
+  },
+};

examples/openapi-ts-axios/src/client/core/params.ts

···
+type Slot = 'body' | 'headers' | 'path' | 'query';
+
+export type Field =
+  | {
+      in: Exclude<Slot, 'body'>;
+      key: string;
+      map?: string;
+    }
+  | {
+      in: Extract<Slot, 'body'>;
+      key?: string;
+      map?: string;
+    };
+
+export interface Fields {
+  allowExtra?: Partial<Record<Slot, boolean>>;
+  args?: ReadonlyArray<Field>;
+}
+
+export type FieldsConfig = ReadonlyArray<Field | Fields>;
+
+const extraPrefixesMap: Record<string, Slot> = {
+  $body_: 'body',
+  $headers_: 'headers',
+  $path_: 'path',
+  $query_: 'query',
+};
+const extraPrefixes = Object.entries(extraPrefixesMap);
+
+type KeyMap = Map<
+  string,
+  {
+    in: Slot;
+    map?: string;
+  }
+>;
+
+const buildKeyMap = (fields: FieldsConfig, map?: KeyMap): KeyMap => {
+  if (!map) {
+    map = new Map();
+  }
+
+  for (const config of fields) {
+    if ('in' in config) {
+      if (config.key) {
+        map.set(config.key, {
+          in: config.in,
+          map: config.map,
+        });
+      }
+    } else if (config.args) {
+      buildKeyMap(config.args, map);
+    }
+  }
+
+  return map;
+};
+
+interface Params {
+  body: unknown;
+  headers: Record<string, unknown>;
+  path: Record<string, unknown>;
+  query: Record<string, unknown>;
+}
+
+const stripEmptySlots = (params: Params) => {
+  for (const [slot, value] of Object.entries(params)) {
+    if (value && typeof value === 'object' && !Object.keys(value).length) {
+      delete params[slot as Slot];
+    }
+  }
+};
+
+export const buildClientParams = (
+  args: ReadonlyArray<unknown>,
+  fields: FieldsConfig,
+) => {
+  const params: Params = {
+    body: {},
+    headers: {},
+    path: {},
+    query: {},
+  };
+
+  const map = buildKeyMap(fields);
+
+  let config: FieldsConfig[number] | undefined;
+
+  for (const [index, arg] of args.entries()) {
+    if (fields[index]) {
+      config = fields[index];
+    }
+
+    if (!config) {
+      continue;
+    }
+
+    if ('in' in config) {
+      if (config.key) {
+        const field = map.get(config.key)!;
+        const name = field.map || config.key;
+        (params[field.in] as Record<string, unknown>)[name] = arg;
+      } else {
+        params.body = arg;
+      }
+    } else {
+      for (const [key, value] of Object.entries(arg ?? {})) {
+        const field = map.get(key);
+
+        if (field) {
+          const name = field.map || key;
+          (params[field.in] as Record<string, unknown>)[name] = value;
+        } else {
+          const extra = extraPrefixes.find(([prefix]) =>
+            key.startsWith(prefix),
+          );
+
+          if (extra) {
+            const [prefix, slot] = extra;
+            (params[slot] as Record<string, unknown>)[
+              key.slice(prefix.length)
+            ] = value;
+          } else {
+            for (const [slot, allowed] of Object.entries(
+              config.allowExtra ?? {},
+            )) {
+              if (allowed) {
+                (params[slot as Slot] as Record<string, unknown>)[key] = value;
+                break;
+              }
+            }
+          }
+        }
+      }
+    }
+  }
+
+  stripEmptySlots(params);
+
+  return params;
+};

examples/openapi-ts-axios/src/client/core/pathSerializer.ts

···
+interface SerializeOptions<T>
+  extends SerializePrimitiveOptions,
+    SerializerOptions<T> {}
+
+interface SerializePrimitiveOptions {
+  allowReserved?: boolean;
+  name: string;
+}
+
+export interface SerializerOptions<T> {
+  /**
+   * @default true
+   */
+  explode: boolean;
+  style: T;
+}
+
+export type ArrayStyle = 'form' | 'spaceDelimited' | 'pipeDelimited';
+export type ArraySeparatorStyle = ArrayStyle | MatrixStyle;
+type MatrixStyle = 'label' | 'matrix' | 'simple';
+export type ObjectStyle = 'form' | 'deepObject';
+type ObjectSeparatorStyle = ObjectStyle | MatrixStyle;
+
+interface SerializePrimitiveParam extends SerializePrimitiveOptions {
+  value: string;
+}
+
+export const separatorArrayExplode = (style: ArraySeparatorStyle) => {
+  switch (style) {
+    case 'label':
+      return '.';
+    case 'matrix':
+      return ';';
+    case 'simple':
+      return ',';
+    default:
+      return '&';
+  }
+};
+
+export const separatorArrayNoExplode = (style: ArraySeparatorStyle) => {
+  switch (style) {
+    case 'form':
+      return ',';
+    case 'pipeDelimited':
+      return '|';
+    case 'spaceDelimited':
+      return '%20';
+    default:
+      return ',';
+  }
+};
+
+export const separatorObjectExplode = (style: ObjectSeparatorStyle) => {
+  switch (style) {
+    case 'label':
+      return '.';
+    case 'matrix':
+      return ';';
+    case 'simple':
+      return ',';
+    default:
+      return '&';
+  }
+};
+
+export const serializeArrayParam = ({
+  allowReserved,
+  explode,
+  name,
+  style,
+  value,
+}: SerializeOptions<ArraySeparatorStyle> & {
+  value: unknown[];
+}) => {
+  if (!explode) {
+    const joinedValues = (
+      allowReserved ? value : value.map((v) => encodeURIComponent(v as string))
+    ).join(separatorArrayNoExplode(style));
+    switch (style) {
+      case 'label':
+        return `.${joinedValues}`;
+      case 'matrix':
+        return `;${name}=${joinedValues}`;
+      case 'simple':
+        return joinedValues;
+      default:
+        return `${name}=${joinedValues}`;
+    }
+  }
+
+  const separator = separatorArrayExplode(style);
+  const joinedValues = value
+    .map((v) => {
+      if (style === 'label' || style === 'simple') {
+        return allowReserved ? v : encodeURIComponent(v as string);
+      }
+
+      return serializePrimitiveParam({
+        allowReserved,
+        name,
+        value: v as string,
+      });
+    })
+    .join(separator);
+  return style === 'label' || style === 'matrix'
+    ? separator + joinedValues
+    : joinedValues;
+};
+
+export const serializePrimitiveParam = ({
+  allowReserved,
+  name,
+  value,
+}: SerializePrimitiveParam) => {
+  if (value === undefined || value === null) {
+    return '';
+  }
+
+  if (typeof value === 'object') {
+    throw new Error(
+      'Deeply-nested arrays/objects aren’t supported. Provide your own `querySerializer()` to handle these.',
+    );
+  }
+
+  return `${name}=${allowReserved ? value : encodeURIComponent(value)}`;
+};
+
+export const serializeObjectParam = ({
+  allowReserved,
+  explode,
+  name,
+  style,
+  value,
+  valueOnly,
+}: SerializeOptions<ObjectSeparatorStyle> & {
+  value: Record<string, unknown> | Date;
+  valueOnly?: boolean;
+}) => {
+  if (value instanceof Date) {
+    return valueOnly ? value.toISOString() : `${name}=${value.toISOString()}`;
+  }
+
+  if (style !== 'deepObject' && !explode) {
+    let values: string[] = [];
+    Object.entries(value).forEach(([key, v]) => {
+      values = [
+        ...values,
+        key,
+        allowReserved ? (v as string) : encodeURIComponent(v as string),
+      ];
+    });
+    const joinedValues = values.join(',');
+    switch (style) {
+      case 'form':
+        return `${name}=${joinedValues}`;
+      case 'label':
+        return `.${joinedValues}`;
+      case 'matrix':
+        return `;${name}=${joinedValues}`;
+      default:
+        return joinedValues;
+    }
+  }
+
+  const separator = separatorObjectExplode(style);
+  const joinedValues = Object.entries(value)
+    .map(([key, v]) =>
+      serializePrimitiveParam({
+        allowReserved,
+        name: style === 'deepObject' ? `${name}[${key}]` : key,
+        value: v as string,
+      }),
+    )
+    .join(separator);
+  return style === 'label' || style === 'matrix'
+    ? separator + joinedValues
+    : joinedValues;
+};

examples/openapi-ts-axios/src/client/core/types.ts

···
+import type { Auth, AuthToken } from './auth';
+import type {
+  BodySerializer,
+  QuerySerializer,
+  QuerySerializerOptions,
+} from './bodySerializer';
+
+export interface Client<
+  RequestFn = never,
+  Config = unknown,
+  MethodFn = never,
+  BuildUrlFn = never,
+> {
+  /**
+   * Returns the final request URL.
+   */
+  buildUrl: BuildUrlFn;
+  connect: MethodFn;
+  delete: MethodFn;
+  get: MethodFn;
+  getConfig: () => Config;
+  head: MethodFn;
+  options: MethodFn;
+  patch: MethodFn;
+  post: MethodFn;
+  put: MethodFn;
+  request: RequestFn;
+  setConfig: (config: Config) => Config;
+  trace: MethodFn;
+}
+
+export interface Config {
+  /**
+   * Auth token or a function returning auth token. The resolved value will be
+   * added to the request payload as defined by its `security` array.
+   */
+  auth?: ((auth: Auth) => Promise<AuthToken> | AuthToken) | AuthToken;
+  /**
+   * A function for serializing request body parameter. By default,
+   * {@link JSON.stringify()} will be used.
+   */
+  bodySerializer?: BodySerializer | null;
+  /**
+   * An object containing any HTTP headers that you want to pre-populate your
+   * `Headers` object with.
+   *
+   * {@link https://developer.mozilla.org/docs/Web/API/Headers/Headers#init See more}
+   */
+  headers?:
+    | RequestInit['headers']
+    | Record<
+        string,
+        | string
+        | number
+        | boolean
+        | (string | number | boolean)[]
+        | null
+        | undefined
+        | unknown
+      >;
+  /**
+   * The request method.
+   *
+   * {@link https://developer.mozilla.org/docs/Web/API/fetch#method See more}
+   */
+  method?:
+    | 'CONNECT'
+    | 'DELETE'
+    | 'GET'
+    | 'HEAD'
+    | 'OPTIONS'
+    | 'PATCH'
+    | 'POST'
+    | 'PUT'
+    | 'TRACE';
+  /**
+   * A function for serializing request query parameters. By default, arrays
+   * will be exploded in form style, objects will be exploded in deepObject
+   * style, and reserved characters are percent-encoded.
+   *
+   * This method will have no effect if the native `paramsSerializer()` Axios
+   * API function is used.
+   *
+   * {@link https://swagger.io/docs/specification/serialization/#query View examples}
+   */
+  querySerializer?: QuerySerializer | QuerySerializerOptions;
+  /**
+   * A function transforming response data before it's returned. This is useful
+   * for post-processing data, e.g. converting ISO strings into Date objects.
+   */
+  responseTransformer?: (data: unknown) => Promise<unknown>;
+  /**
+   * A function validating response data. This is useful if you want to ensure
+   * the response conforms to the desired shape, so it can be safely passed to
+   * the transformers and returned to the user.
+   */
+  responseValidator?: (data: unknown) => Promise<unknown>;
+}

examples/openapi-ts-axios/src/client/sdk.gen.ts

···
 // This file is auto-generated by @hey-api/openapi-ts
 
-import type {
-  Client,
-  Options as ClientOptions,
-  TDataShape,
-} from '@hey-api/client-axios';
-
+import type { Client, Options as ClientOptions, TDataShape } from './client';
 import { client as _heyApiClient } from './client.gen';
 import type {
   AddPetData,
···
     ...options,
     headers: {
       'Content-Type': 'application/json',
-      ...options?.headers,
+      ...options.headers,
     },
   });
 
···
     ...options,
     headers: {
       'Content-Type': 'application/json',
-      ...options?.headers,
+      ...options.headers,
     },
   });
 
···
     ...options,
     headers: {
       'Content-Type': 'application/octet-stream',
-      ...options?.headers,
+      ...options.headers,
     },
   });
 
···
     ...options,
     headers: {
       'Content-Type': 'application/json',
-      ...options?.headers,
+      ...options.headers,
     },
   });

examples/openapi-ts-fastify/openapi-ts.config.ts

···
     lint: 'eslint',
     path: './src/client',
   },
-  plugins: ['@hey-api/client-fetch', 'fastify', '@hey-api/sdk'],
+  plugins: ['fastify', '@hey-api/sdk'],
 });

examples/openapi-ts-fastify/package.json

···
     "typecheck": "tsc --noEmit"
   },
   "dependencies": {
-    "@hey-api/client-fetch": "workspace:*",
     "fastify": "5.2.0",
     "fastify-openapi-glue": "4.8.0"
   },

examples/openapi-ts-fastify/src/client/client.gen.ts

···
   type Config,
   createClient,
   createConfig,
-} from '@hey-api/client-fetch';
-
+} from './client';
 import type { ClientOptions } from './types.gen';
 
 /**

examples/openapi-ts-fastify/src/client/client/client.ts

···
+import type { Client, Config, RequestOptions } from './types';
+import {
+  buildUrl,
+  createConfig,
+  createInterceptors,
+  getParseAs,
+  mergeConfigs,
+  mergeHeaders,
+  setAuthParams,
+} from './utils';
+
+type ReqInit = Omit<RequestInit, 'body' | 'headers'> & {
+  body?: any;
+  headers: ReturnType<typeof mergeHeaders>;
+};
+
+export const createClient = (config: Config = {}): Client => {
+  let _config = mergeConfigs(createConfig(), config);
+
+  const getConfig = (): Config => ({ ..._config });
+
+  const setConfig = (config: Config): Config => {
+    _config = mergeConfigs(_config, config);
+    return getConfig();
+  };
+
+  const interceptors = createInterceptors<
+    Request,
+    Response,
+    unknown,
+    RequestOptions
+  >();
+
+  const request: Client['request'] = async (options) => {
+    const opts = {
+      ..._config,
+      ...options,
+      fetch: options.fetch ?? _config.fetch ?? globalThis.fetch,
+      headers: mergeHeaders(_config.headers, options.headers),
+    };
+
+    if (opts.security) {
+      await setAuthParams({
+        ...opts,
+        security: opts.security,
+      });
+    }
+
+    if (opts.body && opts.bodySerializer) {
+      opts.body = opts.bodySerializer(opts.body);
+    }
+
+    // remove Content-Type header if body is empty to avoid sending invalid requests
+    if (opts.body === undefined || opts.body === '') {
+      opts.headers.delete('Content-Type');
+    }
+
+    const url = buildUrl(opts);
+    const requestInit: ReqInit = {
+      redirect: 'follow',
+      ...opts,
+    };
+
+    let request = new Request(url, requestInit);
+
+    for (const fn of interceptors.request._fns) {
+      if (fn) {
+        request = await fn(request, opts);
+      }
+    }
+
+    // fetch must be assigned here, otherwise it would throw the error:
+    // TypeError: Failed to execute 'fetch' on 'Window': Illegal invocation
+    const _fetch = opts.fetch!;
+    let response = await _fetch(request);
+
+    for (const fn of interceptors.response._fns) {
+      if (fn) {
+        response = await fn(response, request, opts);
+      }
+    }
+
+    const result = {
+      request,
+      response,
+    };
+
+    if (response.ok) {
+      if (
+        response.status === 204 ||
+        response.headers.get('Content-Length') === '0'
+      ) {
+        return opts.responseStyle === 'data'
+          ? {}
+          : {
+              data: {},
+              ...result,
+            };
+      }
+
+      const parseAs =
+        (opts.parseAs === 'auto'
+          ? getParseAs(response.headers.get('Content-Type'))
+          : opts.parseAs) ?? 'json';
+
+      if (parseAs === 'stream') {
+        return opts.responseStyle === 'data'
+          ? response.body
+          : {
+              data: response.body,
+              ...result,
+            };
+      }
+
+      let data = await response[parseAs]();
+      if (parseAs === 'json') {
+        if (opts.responseValidator) {
+          await opts.responseValidator(data);
+        }
+
+        if (opts.responseTransformer) {
+          data = await opts.responseTransformer(data);
+        }
+      }
+
+      return opts.responseStyle === 'data'
+        ? data
+        : {
+            data,
+            ...result,
+          };
+    }
+
+    let error = await response.text();
+
+    try {
+      error = JSON.parse(error);
+    } catch {
+      // noop
+    }
+
+    let finalError = error;
+
+    for (const fn of interceptors.error._fns) {
+      if (fn) {
+        finalError = (await fn(error, response, request, opts)) as string;
+      }
+    }
+
+    finalError = finalError || ({} as string);
+
+    if (opts.throwOnError) {
+      throw finalError;
+    }
+
+    // TODO: we probably want to return error and improve types
+    return opts.responseStyle === 'data'
+      ? undefined
+      : {
+          error: finalError,
+          ...result,
+        };
+  };
+
+  return {
+    buildUrl,
+    connect: (options) => request({ ...options, method: 'CONNECT' }),
+    delete: (options) => request({ ...options, method: 'DELETE' }),
+    get: (options) => request({ ...options, method: 'GET' }),
+    getConfig,
+    head: (options) => request({ ...options, method: 'HEAD' }),
+    interceptors,
+    options: (options) => request({ ...options, method: 'OPTIONS' }),
+    patch: (options) => request({ ...options, method: 'PATCH' }),
+    post: (options) => request({ ...options, method: 'POST' }),
+    put: (options) => request({ ...options, method: 'PUT' }),
+    request,
+    setConfig,
+    trace: (options) => request({ ...options, method: 'TRACE' }),
+  };
+};

examples/openapi-ts-fastify/src/client/client/index.ts

···
+export type { Auth } from '../core/auth';
+export type { QuerySerializerOptions } from '../core/bodySerializer';
+export {
+  formDataBodySerializer,
+  jsonBodySerializer,
+  urlSearchParamsBodySerializer,
+} from '../core/bodySerializer';
+export { buildClientParams } from '../core/params';
+export { createClient } from './client';
+export type {
+  Client,
+  ClientOptions,
+  Config,
+  CreateClientConfig,
+  Options,
+  OptionsLegacyParser,
+  RequestOptions,
+  RequestResult,
+  ResponseStyle,
+  TDataShape,
+} from './types';
+export { createConfig, mergeHeaders } from './utils';

examples/openapi-ts-fastify/src/client/client/types.ts

···
+import type { Auth } from '../core/auth';
+import type { Client as CoreClient, Config as CoreConfig } from '../core/types';
+import type { Middleware } from './utils';
+
+export type ResponseStyle = 'data' | 'fields';
+
+export interface Config<T extends ClientOptions = ClientOptions>
+  extends Omit<RequestInit, 'body' | 'headers' | 'method'>,
+    CoreConfig {
+  /**
+   * Base URL for all requests made by this client.
+   */
+  baseUrl?: T['baseUrl'];
+  /**
+   * Fetch API implementation. You can use this option to provide a custom
+   * fetch instance.
+   *
+   * @default globalThis.fetch
+   */
+  fetch?: (request: Request) => ReturnType<typeof fetch>;
+  /**
+   * Please don't use the Fetch client for Next.js applications. The `next`
+   * options won't have any effect.
+   *
+   * Install {@link https://www.npmjs.com/package/@hey-api/client-next `@hey-api/client-next`} instead.
+   */
+  next?: never;
+  /**
+   * Return the response data parsed in a specified format. By default, `auto`
+   * will infer the appropriate method from the `Content-Type` response header.
+   * You can override this behavior with any of the {@link Body} methods.
+   * Select `stream` if you don't want to parse response data at all.
+   *
+   * @default 'auto'
+   */
+  parseAs?: Exclude<keyof Body, 'body' | 'bodyUsed'> | 'auto' | 'stream';
+  /**
+   * Should we return only data or multiple fields (data, error, response, etc.)?
+   *
+   * @default 'fields'
+   */
+  responseStyle?: ResponseStyle;
+  /**
+   * Throw an error instead of returning it in the response?
+   *
+   * @default false
+   */
+  throwOnError?: T['throwOnError'];
+}
+
+export interface RequestOptions<
+  TResponseStyle extends ResponseStyle = 'fields',
+  ThrowOnError extends boolean = boolean,
+  Url extends string = string,
+> extends Config<{
+    responseStyle: TResponseStyle;
+    throwOnError: ThrowOnError;
+  }> {
+  /**
+   * Any body that you want to add to your request.
+   *
+   * {@link https://developer.mozilla.org/docs/Web/API/fetch#body}
+   */
+  body?: unknown;
+  path?: Record<string, unknown>;
+  query?: Record<string, unknown>;
+  /**
+   * Security mechanism(s) to use for the request.
+   */
+  security?: ReadonlyArray<Auth>;
+  url: Url;
+}
+
+export type RequestResult<
+  TData = unknown,
+  TError = unknown,
+  ThrowOnError extends boolean = boolean,
+  TResponseStyle extends ResponseStyle = 'fields',
+> = ThrowOnError extends true
+  ? Promise<
+      TResponseStyle extends 'data'
+        ? TData extends Record<string, unknown>
+          ? TData[keyof TData]
+          : TData
+        : {
+            data: TData extends Record<string, unknown>
+              ? TData[keyof TData]
+              : TData;
+            request: Request;
+            response: Response;
+          }
+    >
+  : Promise<
+      TResponseStyle extends 'data'
+        ?
+            | (TData extends Record<string, unknown>
+                ? TData[keyof TData]
+                : TData)
+            | undefined
+        : (
+            | {
+                data: TData extends Record<string, unknown>
+                  ? TData[keyof TData]
+                  : TData;
+                error: undefined;
+              }
+            | {
+                data: undefined;
+                error: TError extends Record<string, unknown>
+                  ? TError[keyof TError]
+                  : TError;
+              }
+          ) & {
+            request: Request;
+            response: Response;
+          }
+    >;
+
+export interface ClientOptions {
+  baseUrl?: string;
+  responseStyle?: ResponseStyle;
+  throwOnError?: boolean;
+}
+
+type MethodFn = <
+  TData = unknown,
+  TError = unknown,
+  ThrowOnError extends boolean = false,
+  TResponseStyle extends ResponseStyle = 'fields',
+>(
+  options: Omit<RequestOptions<TResponseStyle, ThrowOnError>, 'method'>,
+) => RequestResult<TData, TError, ThrowOnError, TResponseStyle>;
+
+type RequestFn = <
+  TData = unknown,
+  TError = unknown,
+  ThrowOnError extends boolean = false,
+  TResponseStyle extends ResponseStyle = 'fields',
+>(
+  options: Omit<RequestOptions<TResponseStyle, ThrowOnError>, 'method'> &
+    Pick<Required<RequestOptions<TResponseStyle, ThrowOnError>>, 'method'>,
+) => RequestResult<TData, TError, ThrowOnError, TResponseStyle>;
+
+type BuildUrlFn = <
+  TData extends {
+    body?: unknown;
+    path?: Record<string, unknown>;
+    query?: Record<string, unknown>;
+    url: string;
+  },
+>(
+  options: Pick<TData, 'url'> & Options<TData>,
+) => string;
+
+export type Client = CoreClient<RequestFn, Config, MethodFn, BuildUrlFn> & {
+  interceptors: Middleware<Request, Response, unknown, RequestOptions>;
+};
+
+/**
+ * The `createClientConfig()` function will be called on client initialization
+ * and the returned object will become the client's initial configuration.
+ *
+ * You may want to initialize your client this way instead of calling
+ * `setConfig()`. This is useful for example if you're using Next.js
+ * to ensure your client always has the correct values.
+ */
+export type CreateClientConfig<T extends ClientOptions = ClientOptions> = (
+  override?: Config<ClientOptions & T>,
+) => Config<Required<ClientOptions> & T>;
+
+export interface TDataShape {
+  body?: unknown;
+  headers?: unknown;
+  path?: unknown;
+  query?: unknown;
+  url: string;
+}
+
+type OmitKeys<T, K> = Pick<T, Exclude<keyof T, K>>;
+
+export type Options<
+  TData extends TDataShape = TDataShape,
+  ThrowOnError extends boolean = boolean,
+  TResponseStyle extends ResponseStyle = 'fields',
+> = OmitKeys<
+  RequestOptions<TResponseStyle, ThrowOnError>,
+  'body' | 'path' | 'query' | 'url'
+> &
+  Omit<TData, 'url'>;
+
+export type OptionsLegacyParser<
+  TData = unknown,
+  ThrowOnError extends boolean = boolean,
+  TResponseStyle extends ResponseStyle = 'fields',
+> = TData extends { body?: any }
+  ? TData extends { headers?: any }
+    ? OmitKeys<
+        RequestOptions<TResponseStyle, ThrowOnError>,
+        'body' | 'headers' | 'url'
+      > &
+        TData
+    : OmitKeys<RequestOptions<TResponseStyle, ThrowOnError>, 'body' | 'url'> &
+        TData &
+        Pick<RequestOptions<TResponseStyle, ThrowOnError>, 'headers'>
+  : TData extends { headers?: any }
+    ? OmitKeys<
+        RequestOptions<TResponseStyle, ThrowOnError>,
+        'headers' | 'url'
+      > &
+        TData &
+        Pick<RequestOptions<TResponseStyle, ThrowOnError>, 'body'>
+    : OmitKeys<RequestOptions<TResponseStyle, ThrowOnError>, 'url'> & TData;

examples/openapi-ts-fastify/src/client/client/utils.ts

···
+import { getAuthToken } from '../core/auth';
+import type {
+  QuerySerializer,
+  QuerySerializerOptions,
+} from '../core/bodySerializer';
+import { jsonBodySerializer } from '../core/bodySerializer';
+import {
+  serializeArrayParam,
+  serializeObjectParam,
+  serializePrimitiveParam,
+} from '../core/pathSerializer';
+import type { Client, ClientOptions, Config, RequestOptions } from './types';
+
+interface PathSerializer {
+  path: Record<string, unknown>;
+  url: string;
+}
+
+const PATH_PARAM_RE = /\{[^{}]+\}/g;
+
+type ArrayStyle = 'form' | 'spaceDelimited' | 'pipeDelimited';
+type MatrixStyle = 'label' | 'matrix' | 'simple';
+type ArraySeparatorStyle = ArrayStyle | MatrixStyle;
+
+const defaultPathSerializer = ({ path, url: _url }: PathSerializer) => {
+  let url = _url;
+  const matches = _url.match(PATH_PARAM_RE);
+  if (matches) {
+    for (const match of matches) {
+      let explode = false;
+      let name = match.substring(1, match.length - 1);
+      let style: ArraySeparatorStyle = 'simple';
+
+      if (name.endsWith('*')) {
+        explode = true;
+        name = name.substring(0, name.length - 1);
+      }
+
+      if (name.startsWith('.')) {
+        name = name.substring(1);
+        style = 'label';
+      } else if (name.startsWith(';')) {
+        name = name.substring(1);
+        style = 'matrix';
+      }
+
+      const value = path[name];
+
+      if (value === undefined || value === null) {
+        continue;
+      }
+
+      if (Array.isArray(value)) {
+        url = url.replace(
+          match,
+          serializeArrayParam({ explode, name, style, value }),
+        );
+        continue;
+      }
+
+      if (typeof value === 'object') {
+        url = url.replace(
+          match,
+          serializeObjectParam({
+            explode,
+            name,
+            style,
+            value: value as Record<string, unknown>,
+            valueOnly: true,
+          }),
+        );
+        continue;
+      }
+
+      if (style === 'matrix') {
+        url = url.replace(
+          match,
+          `;${serializePrimitiveParam({
+            name,
+            value: value as string,
+          })}`,
+        );
+        continue;
+      }
+
+      const replaceValue = encodeURIComponent(
+        style === 'label' ? `.${value as string}` : (value as string),
+      );
+      url = url.replace(match, replaceValue);
+    }
+  }
+  return url;
+};
+
+export const createQuerySerializer = <T = unknown>({
+  allowReserved,
+  array,
+  object,
+}: QuerySerializerOptions = {}) => {
+  const querySerializer = (queryParams: T) => {
+    const search: string[] = [];
+    if (queryParams && typeof queryParams === 'object') {
+      for (const name in queryParams) {
+        const value = queryParams[name];
+
+        if (value === undefined || value === null) {
+          continue;
+        }
+
+        if (Array.isArray(value)) {
+          const serializedArray = serializeArrayParam({
+            allowReserved,
+            explode: true,
+            name,
+            style: 'form',
+            value,
+            ...array,
+          });
+          if (serializedArray) search.push(serializedArray);
+        } else if (typeof value === 'object') {
+          const serializedObject = serializeObjectParam({
+            allowReserved,
+            explode: true,
+            name,
+            style: 'deepObject',
+            value: value as Record<string, unknown>,
+            ...object,
+          });
+          if (serializedObject) search.push(serializedObject);
+        } else {
+          const serializedPrimitive = serializePrimitiveParam({
+            allowReserved,
+            name,
+            value: value as string,
+          });
+          if (serializedPrimitive) search.push(serializedPrimitive);
+        }
+      }
+    }
+    return search.join('&');
+  };
+  return querySerializer;
+};
+
+/**
+ * Infers parseAs value from provided Content-Type header.
+ */
+export const getParseAs = (
+  contentType: string | null,
+): Exclude<Config['parseAs'], 'auto'> => {
+  if (!contentType) {
+    // If no Content-Type header is provided, the best we can do is return the raw response body,
+    // which is effectively the same as the 'stream' option.
+    return 'stream';
+  }
+
+  const cleanContent = contentType.split(';')[0]?.trim();
+
+  if (!cleanContent) {
+    return;
+  }
+
+  if (
+    cleanContent.startsWith('application/json') ||
+    cleanContent.endsWith('+json')
+  ) {
+    return 'json';
+  }
+
+  if (cleanContent === 'multipart/form-data') {
+    return 'formData';
+  }
+
+  if (
+    ['application/', 'audio/', 'image/', 'video/'].some((type) =>
+      cleanContent.startsWith(type),
+    )
+  ) {
+    return 'blob';
+  }
+
+  if (cleanContent.startsWith('text/')) {
+    return 'text';
+  }
+};
+
+export const setAuthParams = async ({
+  security,
+  ...options
+}: Pick<Required<RequestOptions>, 'security'> &
+  Pick<RequestOptions, 'auth' | 'query'> & {
+    headers: Headers;
+  }) => {
+  for (const auth of security) {
+    const token = await getAuthToken(auth, options.auth);
+
+    if (!token) {
+      continue;
+    }
+
+    const name = auth.name ?? 'Authorization';
+
+    switch (auth.in) {
+      case 'query':
+        if (!options.query) {
+          options.query = {};
+        }
+        options.query[name] = token;
+        break;
+      case 'cookie':
+        options.headers.append('Cookie', `${name}=${token}`);
+        break;
+      case 'header':
+      default:
+        options.headers.set(name, token);
+        break;
+    }
+
+    return;
+  }
+};
+
+export const buildUrl: Client['buildUrl'] = (options) => {
+  const url = getUrl({
+    baseUrl: options.baseUrl as string,
+    path: options.path,
+    query: options.query,
+    querySerializer:
+      typeof options.querySerializer === 'function'
+        ? options.querySerializer
+        : createQuerySerializer(options.querySerializer),
+    url: options.url,
+  });
+  return url;
+};
+
+export const getUrl = ({
+  baseUrl,
+  path,
+  query,
+  querySerializer,
+  url: _url,
+}: {
+  baseUrl?: string;
+  path?: Record<string, unknown>;
+  query?: Record<string, unknown>;
+  querySerializer: QuerySerializer;
+  url: string;
+}) => {
+  const pathUrl = _url.startsWith('/') ? _url : `/${_url}`;
+  let url = (baseUrl ?? '') + pathUrl;
+  if (path) {
+    url = defaultPathSerializer({ path, url });
+  }
+  let search = query ? querySerializer(query) : '';
+  if (search.startsWith('?')) {
+    search = search.substring(1);
+  }
+  if (search) {
+    url += `?${search}`;
+  }
+  return url;
+};
+
+export const mergeConfigs = (a: Config, b: Config): Config => {
+  const config = { ...a, ...b };
+  if (config.baseUrl?.endsWith('/')) {
+    config.baseUrl = config.baseUrl.substring(0, config.baseUrl.length - 1);
+  }
+  config.headers = mergeHeaders(a.headers, b.headers);
+  return config;
+};
+
+export const mergeHeaders = (
+  ...headers: Array<Required<Config>['headers'] | undefined>
+): Headers => {
+  const mergedHeaders = new Headers();
+  for (const header of headers) {
+    if (!header || typeof header !== 'object') {
+      continue;
+    }
+
+    const iterator =
+      header instanceof Headers ? header.entries() : Object.entries(header);
+
+    for (const [key, value] of iterator) {
+      if (value === null) {
+        mergedHeaders.delete(key);
+      } else if (Array.isArray(value)) {
+        for (const v of value) {
+          mergedHeaders.append(key, v as string);
+        }
+      } else if (value !== undefined) {
+        // assume object headers are meant to be JSON stringified, i.e. their
+        // content value in OpenAPI specification is 'application/json'
+        mergedHeaders.set(
+          key,
+          typeof value === 'object' ? JSON.stringify(value) : (value as string),
+        );
+      }
+    }
+  }
+  return mergedHeaders;
+};
+
+type ErrInterceptor<Err, Res, Req, Options> = (
+  error: Err,
+  response: Res,
+  request: Req,
+  options: Options,
+) => Err | Promise<Err>;
+
+type ReqInterceptor<Req, Options> = (
+  request: Req,
+  options: Options,
+) => Req | Promise<Req>;
+
+type ResInterceptor<Res, Req, Options> = (
+  response: Res,
+  request: Req,
+  options: Options,
+) => Res | Promise<Res>;
+
+class Interceptors<Interceptor> {
+  _fns: (Interceptor | null)[];
+
+  constructor() {
+    this._fns = [];
+  }
+
+  clear() {
+    this._fns = [];
+  }
+
+  getInterceptorIndex(id: number | Interceptor): number {
+    if (typeof id === 'number') {
+      return this._fns[id] ? id : -1;
+    } else {
+      return this._fns.indexOf(id);
+    }
+  }
+  exists(id: number | Interceptor) {
+    const index = this.getInterceptorIndex(id);
+    return !!this._fns[index];
+  }
+
+  eject(id: number | Interceptor) {
+    const index = this.getInterceptorIndex(id);
+    if (this._fns[index]) {
+      this._fns[index] = null;
+    }
+  }
+
+  update(id: number | Interceptor, fn: Interceptor) {
+    const index = this.getInterceptorIndex(id);
+    if (this._fns[index]) {
+      this._fns[index] = fn;
+      return id;
+    } else {
+      return false;
+    }
+  }
+
+  use(fn: Interceptor) {
+    this._fns = [...this._fns, fn];
+    return this._fns.length - 1;
+  }
+}
+
+// `createInterceptors()` response, meant for external use as it does not
+// expose internals
+export interface Middleware<Req, Res, Err, Options> {
+  error: Pick<
+    Interceptors<ErrInterceptor<Err, Res, Req, Options>>,
+    'eject' | 'use'
+  >;
+  request: Pick<Interceptors<ReqInterceptor<Req, Options>>, 'eject' | 'use'>;
+  response: Pick<
+    Interceptors<ResInterceptor<Res, Req, Options>>,
+    'eject' | 'use'
+  >;
+}
+
+// do not add `Middleware` as return type so we can use _fns internally
+export const createInterceptors = <Req, Res, Err, Options>() => ({
+  error: new Interceptors<ErrInterceptor<Err, Res, Req, Options>>(),
+  request: new Interceptors<ReqInterceptor<Req, Options>>(),
+  response: new Interceptors<ResInterceptor<Res, Req, Options>>(),
+});
+
+const defaultQuerySerializer = createQuerySerializer({
+  allowReserved: false,
+  array: {
+    explode: true,
+    style: 'form',
+  },
+  object: {
+    explode: true,
+    style: 'deepObject',
+  },
+});
+
+const defaultHeaders = {
+  'Content-Type': 'application/json',
+};
+
+export const createConfig = <T extends ClientOptions = ClientOptions>(
+  override: Config<Omit<ClientOptions, keyof T> & T> = {},
+): Config<Omit<ClientOptions, keyof T> & T> => ({
+  ...jsonBodySerializer,
+  headers: defaultHeaders,
+  parseAs: 'auto',
+  querySerializer: defaultQuerySerializer,
+  ...override,
+});

examples/openapi-ts-fastify/src/client/core/auth.ts

···
+export type AuthToken = string | undefined;
+
+export interface Auth {
+  /**
+   * Which part of the request do we use to send the auth?
+   *
+   * @default 'header'
+   */
+  in?: 'header' | 'query' | 'cookie';
+  /**
+   * Header or query parameter name.
+   *
+   * @default 'Authorization'
+   */
+  name?: string;
+  scheme?: 'basic' | 'bearer';
+  type: 'apiKey' | 'http';
+}
+
+export const getAuthToken = async (
+  auth: Auth,
+  callback: ((auth: Auth) => Promise<AuthToken> | AuthToken) | AuthToken,
+): Promise<string | undefined> => {
+  const token =
+    typeof callback === 'function' ? await callback(auth) : callback;
+
+  if (!token) {
+    return;
+  }
+
+  if (auth.scheme === 'bearer') {
+    return `Bearer ${token}`;
+  }
+
+  if (auth.scheme === 'basic') {
+    return `Basic ${btoa(token)}`;
+  }
+
+  return token;
+};

examples/openapi-ts-fastify/src/client/core/bodySerializer.ts

···
+import type {
+  ArrayStyle,
+  ObjectStyle,
+  SerializerOptions,
+} from './pathSerializer';
+
+export type QuerySerializer = (query: Record<string, unknown>) => string;
+
+export type BodySerializer = (body: any) => any;
+
+export interface QuerySerializerOptions {
+  allowReserved?: boolean;
+  array?: SerializerOptions<ArrayStyle>;
+  object?: SerializerOptions<ObjectStyle>;
+}
+
+const serializeFormDataPair = (data: FormData, key: string, value: unknown) => {
+  if (typeof value === 'string' || value instanceof Blob) {
+    data.append(key, value);
+  } else {
+    data.append(key, JSON.stringify(value));
+  }
+};
+
+const serializeUrlSearchParamsPair = (
+  data: URLSearchParams,
+  key: string,
+  value: unknown,
+) => {
+  if (typeof value === 'string') {
+    data.append(key, value);
+  } else {
+    data.append(key, JSON.stringify(value));
+  }
+};
+
+export const formDataBodySerializer = {
+  bodySerializer: <T extends Record<string, any> | Array<Record<string, any>>>(
+    body: T,
+  ) => {
+    const data = new FormData();
+
+    Object.entries(body).forEach(([key, value]) => {
+      if (value === undefined || value === null) {
+        return;
+      }
+      if (Array.isArray(value)) {
+        value.forEach((v) => serializeFormDataPair(data, key, v));
+      } else {
+        serializeFormDataPair(data, key, value);
+      }
+    });
+
+    return data;
+  },
+};
+
+export const jsonBodySerializer = {
+  bodySerializer: <T>(body: T) =>
+    JSON.stringify(body, (key, value) =>
+      typeof value === 'bigint' ? value.toString() : value,
+    ),
+};
+
+export const urlSearchParamsBodySerializer = {
+  bodySerializer: <T extends Record<string, any> | Array<Record<string, any>>>(
+    body: T,
+  ) => {
+    const data = new URLSearchParams();
+
+    Object.entries(body).forEach(([key, value]) => {
+      if (value === undefined || value === null) {
+        return;
+      }
+      if (Array.isArray(value)) {
+        value.forEach((v) => serializeUrlSearchParamsPair(data, key, v));
+      } else {
+        serializeUrlSearchParamsPair(data, key, value);
+      }
+    });
+
+    return data.toString();
+  },
+};

examples/openapi-ts-fastify/src/client/core/params.ts

···
+type Slot = 'body' | 'headers' | 'path' | 'query';
+
+export type Field =
+  | {
+      in: Exclude<Slot, 'body'>;
+      key: string;
+      map?: string;
+    }
+  | {
+      in: Extract<Slot, 'body'>;
+      key?: string;
+      map?: string;
+    };
+
+export interface Fields {
+  allowExtra?: Partial<Record<Slot, boolean>>;
+  args?: ReadonlyArray<Field>;
+}
+
+export type FieldsConfig = ReadonlyArray<Field | Fields>;
+
+const extraPrefixesMap: Record<string, Slot> = {
+  $body_: 'body',
+  $headers_: 'headers',
+  $path_: 'path',
+  $query_: 'query',
+};
+const extraPrefixes = Object.entries(extraPrefixesMap);
+
+type KeyMap = Map<
+  string,
+  {
+    in: Slot;
+    map?: string;
+  }
+>;
+
+const buildKeyMap = (fields: FieldsConfig, map?: KeyMap): KeyMap => {
+  if (!map) {
+    map = new Map();
+  }
+
+  for (const config of fields) {
+    if ('in' in config) {
+      if (config.key) {
+        map.set(config.key, {
+          in: config.in,
+          map: config.map,
+        });
+      }
+    } else if (config.args) {
+      buildKeyMap(config.args, map);
+    }
+  }
+
+  return map;
+};
+
+interface Params {
+  body: unknown;
+  headers: Record<string, unknown>;
+  path: Record<string, unknown>;
+  query: Record<string, unknown>;
+}
+
+const stripEmptySlots = (params: Params) => {
+  for (const [slot, value] of Object.entries(params)) {
+    if (value && typeof value === 'object' && !Object.keys(value).length) {
+      delete params[slot as Slot];
+    }
+  }
+};
+
+export const buildClientParams = (
+  args: ReadonlyArray<unknown>,
+  fields: FieldsConfig,
+) => {
+  const params: Params = {
+    body: {},
+    headers: {},
+    path: {},
+    query: {},
+  };
+
+  const map = buildKeyMap(fields);
+
+  let config: FieldsConfig[number] | undefined;
+
+  for (const [index, arg] of args.entries()) {
+    if (fields[index]) {
+      config = fields[index];
+    }
+
+    if (!config) {
+      continue;
+    }
+
+    if ('in' in config) {
+      if (config.key) {
+        const field = map.get(config.key)!;
+        const name = field.map || config.key;
+        (params[field.in] as Record<string, unknown>)[name] = arg;
+      } else {
+        params.body = arg;
+      }
+    } else {
+      for (const [key, value] of Object.entries(arg ?? {})) {
+        const field = map.get(key);
+
+        if (field) {
+          const name = field.map || key;
+          (params[field.in] as Record<string, unknown>)[name] = value;
+        } else {
+          const extra = extraPrefixes.find(([prefix]) =>
+            key.startsWith(prefix),
+          );
+
+          if (extra) {
+            const [prefix, slot] = extra;
+            (params[slot] as Record<string, unknown>)[
+              key.slice(prefix.length)
+            ] = value;
+          } else {
+            for (const [slot, allowed] of Object.entries(
+              config.allowExtra ?? {},
+            )) {
+              if (allowed) {
+                (params[slot as Slot] as Record<string, unknown>)[key] = value;
+                break;
+              }
+            }
+          }
+        }
+      }
+    }
+  }
+
+  stripEmptySlots(params);
+
+  return params;
+};

examples/openapi-ts-fastify/src/client/core/pathSerializer.ts

···
+interface SerializeOptions<T>
+  extends SerializePrimitiveOptions,
+    SerializerOptions<T> {}
+
+interface SerializePrimitiveOptions {
+  allowReserved?: boolean;
+  name: string;
+}
+
+export interface SerializerOptions<T> {
+  /**
+   * @default true
+   */
+  explode: boolean;
+  style: T;
+}
+
+export type ArrayStyle = 'form' | 'spaceDelimited' | 'pipeDelimited';
+export type ArraySeparatorStyle = ArrayStyle | MatrixStyle;
+type MatrixStyle = 'label' | 'matrix' | 'simple';
+export type ObjectStyle = 'form' | 'deepObject';
+type ObjectSeparatorStyle = ObjectStyle | MatrixStyle;
+
+interface SerializePrimitiveParam extends SerializePrimitiveOptions {
+  value: string;
+}
+
+export const separatorArrayExplode = (style: ArraySeparatorStyle) => {
+  switch (style) {
+    case 'label':
+      return '.';
+    case 'matrix':
+      return ';';
+    case 'simple':
+      return ',';
+    default:
+      return '&';
+  }
+};
+
+export const separatorArrayNoExplode = (style: ArraySeparatorStyle) => {
+  switch (style) {
+    case 'form':
+      return ',';
+    case 'pipeDelimited':
+      return '|';
+    case 'spaceDelimited':
+      return '%20';
+    default:
+      return ',';
+  }
+};
+
+export const separatorObjectExplode = (style: ObjectSeparatorStyle) => {
+  switch (style) {
+    case 'label':
+      return '.';
+    case 'matrix':
+      return ';';
+    case 'simple':
+      return ',';
+    default:
+      return '&';
+  }
+};
+
+export const serializeArrayParam = ({
+  allowReserved,
+  explode,
+  name,
+  style,
+  value,
+}: SerializeOptions<ArraySeparatorStyle> & {
+  value: unknown[];
+}) => {
+  if (!explode) {
+    const joinedValues = (
+      allowReserved ? value : value.map((v) => encodeURIComponent(v as string))
+    ).join(separatorArrayNoExplode(style));
+    switch (style) {
+      case 'label':
+        return `.${joinedValues}`;
+      case 'matrix':
+        return `;${name}=${joinedValues}`;
+      case 'simple':
+        return joinedValues;
+      default:
+        return `${name}=${joinedValues}`;
+    }
+  }
+
+  const separator = separatorArrayExplode(style);
+  const joinedValues = value
+    .map((v) => {
+      if (style === 'label' || style === 'simple') {
+        return allowReserved ? v : encodeURIComponent(v as string);
+      }
+
+      return serializePrimitiveParam({
+        allowReserved,
+        name,
+        value: v as string,
+      });
+    })
+    .join(separator);
+  return style === 'label' || style === 'matrix'
+    ? separator + joinedValues
+    : joinedValues;
+};
+
+export const serializePrimitiveParam = ({
+  allowReserved,
+  name,
+  value,
+}: SerializePrimitiveParam) => {
+  if (value === undefined || value === null) {
+    return '';
+  }
+
+  if (typeof value === 'object') {
+    throw new Error(
+      'Deeply-nested arrays/objects aren’t supported. Provide your own `querySerializer()` to handle these.',
+    );
+  }
+
+  return `${name}=${allowReserved ? value : encodeURIComponent(value)}`;
+};
+
+export const serializeObjectParam = ({
+  allowReserved,
+  explode,
+  name,
+  style,
+  value,
+  valueOnly,
+}: SerializeOptions<ObjectSeparatorStyle> & {
+  value: Record<string, unknown> | Date;
+  valueOnly?: boolean;
+}) => {
+  if (value instanceof Date) {
+    return valueOnly ? value.toISOString() : `${name}=${value.toISOString()}`;
+  }
+
+  if (style !== 'deepObject' && !explode) {
+    let values: string[] = [];
+    Object.entries(value).forEach(([key, v]) => {
+      values = [
+        ...values,
+        key,
+        allowReserved ? (v as string) : encodeURIComponent(v as string),
+      ];
+    });
+    const joinedValues = values.join(',');
+    switch (style) {
+      case 'form':
+        return `${name}=${joinedValues}`;
+      case 'label':
+        return `.${joinedValues}`;
+      case 'matrix':
+        return `;${name}=${joinedValues}`;
+      default:
+        return joinedValues;
+    }
+  }
+
+  const separator = separatorObjectExplode(style);
+  const joinedValues = Object.entries(value)
+    .map(([key, v]) =>
+      serializePrimitiveParam({
+        allowReserved,
+        name: style === 'deepObject' ? `${name}[${key}]` : key,
+        value: v as string,
+      }),
+    )
+    .join(separator);
+  return style === 'label' || style === 'matrix'
+    ? separator + joinedValues
+    : joinedValues;
+};

examples/openapi-ts-fastify/src/client/core/types.ts

···
+import type { Auth, AuthToken } from './auth';
+import type {
+  BodySerializer,
+  QuerySerializer,
+  QuerySerializerOptions,
+} from './bodySerializer';
+
+export interface Client<
+  RequestFn = never,
+  Config = unknown,
+  MethodFn = never,
+  BuildUrlFn = never,
+> {
+  /**
+   * Returns the final request URL.
+   */
+  buildUrl: BuildUrlFn;
+  connect: MethodFn;
+  delete: MethodFn;
+  get: MethodFn;
+  getConfig: () => Config;
+  head: MethodFn;
+  options: MethodFn;
+  patch: MethodFn;
+  post: MethodFn;
+  put: MethodFn;
+  request: RequestFn;
+  setConfig: (config: Config) => Config;
+  trace: MethodFn;
+}
+
+export interface Config {
+  /**
+   * Auth token or a function returning auth token. The resolved value will be
+   * added to the request payload as defined by its `security` array.
+   */
+  auth?: ((auth: Auth) => Promise<AuthToken> | AuthToken) | AuthToken;
+  /**
+   * A function for serializing request body parameter. By default,
+   * {@link JSON.stringify()} will be used.
+   */
+  bodySerializer?: BodySerializer | null;
+  /**
+   * An object containing any HTTP headers that you want to pre-populate your
+   * `Headers` object with.
+   *
+   * {@link https://developer.mozilla.org/docs/Web/API/Headers/Headers#init See more}
+   */
+  headers?:
+    | RequestInit['headers']
+    | Record<
+        string,
+        | string
+        | number
+        | boolean
+        | (string | number | boolean)[]
+        | null
+        | undefined
+        | unknown
+      >;
+  /**
+   * The request method.
+   *
+   * {@link https://developer.mozilla.org/docs/Web/API/fetch#method See more}
+   */
+  method?:
+    | 'CONNECT'
+    | 'DELETE'
+    | 'GET'
+    | 'HEAD'
+    | 'OPTIONS'
+    | 'PATCH'
+    | 'POST'
+    | 'PUT'
+    | 'TRACE';
+  /**
+   * A function for serializing request query parameters. By default, arrays
+   * will be exploded in form style, objects will be exploded in deepObject
+   * style, and reserved characters are percent-encoded.
+   *
+   * This method will have no effect if the native `paramsSerializer()` Axios
+   * API function is used.
+   *
+   * {@link https://swagger.io/docs/specification/serialization/#query View examples}
+   */
+  querySerializer?: QuerySerializer | QuerySerializerOptions;
+  /**
+   * A function transforming response data before it's returned. This is useful
+   * for post-processing data, e.g. converting ISO strings into Date objects.
+   */
+  responseTransformer?: (data: unknown) => Promise<unknown>;
+  /**
+   * A function validating response data. This is useful if you want to ensure
+   * the response conforms to the desired shape, so it can be safely passed to
+   * the transformers and returned to the user.
+   */
+  responseValidator?: (data: unknown) => Promise<unknown>;
+}

examples/openapi-ts-fastify/src/client/sdk.gen.ts

···
 // This file is auto-generated by @hey-api/openapi-ts
 
-import type {
-  Client,
-  Options as ClientOptions,
-  TDataShape,
-} from '@hey-api/client-fetch';
-
+import type { Client, Options as ClientOptions, TDataShape } from './client';
 import { client as _heyApiClient } from './client.gen';
 import type {
   CreatePetsData,

examples/openapi-ts-fetch/package.json

···
     "typecheck": "tsc --noEmit"
   },
   "dependencies": {
-    "@hey-api/client-fetch": "workspace:*",
     "@radix-ui/react-form": "0.1.1",
     "@radix-ui/react-icons": "1.3.2",
     "@radix-ui/themes": "3.1.6",

examples/openapi-ts-fetch/src/App.tsx

···
 import './App.css';
 
-import { createClient } from '@hey-api/client-fetch';
 import * as Form from '@radix-ui/react-form';
 import { DownloadIcon, PlusIcon, ReloadIcon } from '@radix-ui/react-icons';
 import {
···
 } from '@radix-ui/themes';
 import { useState } from 'react';
 
+import { createClient } from './client/client';
 import { PetSchema } from './client/schemas.gen';
 import { addPet, getPetById, updatePet } from './client/sdk.gen';
 import type { Pet } from './client/types.gen';

examples/openapi-ts-fetch/src/client/client.gen.ts

···
   type Config,
   createClient,
   createConfig,
-} from '@hey-api/client-fetch';
-
+} from './client';
 import type { ClientOptions } from './types.gen';
 
 /**

examples/openapi-ts-fetch/src/client/client/client.ts

···
+import type { Client, Config, RequestOptions } from './types';
+import {
+  buildUrl,
+  createConfig,
+  createInterceptors,
+  getParseAs,
+  mergeConfigs,
+  mergeHeaders,
+  setAuthParams,
+} from './utils';
+
+type ReqInit = Omit<RequestInit, 'body' | 'headers'> & {
+  body?: any;
+  headers: ReturnType<typeof mergeHeaders>;
+};
+
+export const createClient = (config: Config = {}): Client => {
+  let _config = mergeConfigs(createConfig(), config);
+
+  const getConfig = (): Config => ({ ..._config });
+
+  const setConfig = (config: Config): Config => {
+    _config = mergeConfigs(_config, config);
+    return getConfig();
+  };
+
+  const interceptors = createInterceptors<
+    Request,
+    Response,
+    unknown,
+    RequestOptions
+  >();
+
+  const request: Client['request'] = async (options) => {
+    const opts = {
+      ..._config,
+      ...options,
+      fetch: options.fetch ?? _config.fetch ?? globalThis.fetch,
+      headers: mergeHeaders(_config.headers, options.headers),
+    };
+
+    if (opts.security) {
+      await setAuthParams({
+        ...opts,
+        security: opts.security,
+      });
+    }
+
+    if (opts.body && opts.bodySerializer) {
+      opts.body = opts.bodySerializer(opts.body);
+    }
+
+    // remove Content-Type header if body is empty to avoid sending invalid requests
+    if (opts.body === undefined || opts.body === '') {
+      opts.headers.delete('Content-Type');
+    }
+
+    const url = buildUrl(opts);
+    const requestInit: ReqInit = {
+      redirect: 'follow',
+      ...opts,
+    };
+
+    let request = new Request(url, requestInit);
+
+    for (const fn of interceptors.request._fns) {
+      if (fn) {
+        request = await fn(request, opts);
+      }
+    }
+
+    // fetch must be assigned here, otherwise it would throw the error:
+    // TypeError: Failed to execute 'fetch' on 'Window': Illegal invocation
+    const _fetch = opts.fetch!;
+    let response = await _fetch(request);
+
+    for (const fn of interceptors.response._fns) {
+      if (fn) {
+        response = await fn(response, request, opts);
+      }
+    }
+
+    const result = {
+      request,
+      response,
+    };
+
+    if (response.ok) {
+      if (
+        response.status === 204 ||
+        response.headers.get('Content-Length') === '0'
+      ) {
+        return opts.responseStyle === 'data'
+          ? {}
+          : {
+              data: {},
+              ...result,
+            };
+      }
+
+      const parseAs =
+        (opts.parseAs === 'auto'
+          ? getParseAs(response.headers.get('Content-Type'))
+          : opts.parseAs) ?? 'json';
+
+      if (parseAs === 'stream') {
+        return opts.responseStyle === 'data'
+          ? response.body
+          : {
+              data: response.body,
+              ...result,
+            };
+      }
+
+      let data = await response[parseAs]();
+      if (parseAs === 'json') {
+        if (opts.responseValidator) {
+          await opts.responseValidator(data);
+        }
+
+        if (opts.responseTransformer) {
+          data = await opts.responseTransformer(data);
+        }
+      }
+
+      return opts.responseStyle === 'data'
+        ? data
+        : {
+            data,
+            ...result,
+          };
+    }
+
+    let error = await response.text();
+
+    try {
+      error = JSON.parse(error);
+    } catch {
+      // noop
+    }
+
+    let finalError = error;
+
+    for (const fn of interceptors.error._fns) {
+      if (fn) {
+        finalError = (await fn(error, response, request, opts)) as string;
+      }
+    }
+
+    finalError = finalError || ({} as string);
+
+    if (opts.throwOnError) {
+      throw finalError;
+    }
+
+    // TODO: we probably want to return error and improve types
+    return opts.responseStyle === 'data'
+      ? undefined
+      : {
+          error: finalError,
+          ...result,
+        };
+  };
+
+  return {
+    buildUrl,
+    connect: (options) => request({ ...options, method: 'CONNECT' }),
+    delete: (options) => request({ ...options, method: 'DELETE' }),
+    get: (options) => request({ ...options, method: 'GET' }),
+    getConfig,
+    head: (options) => request({ ...options, method: 'HEAD' }),
+    interceptors,
+    options: (options) => request({ ...options, method: 'OPTIONS' }),
+    patch: (options) => request({ ...options, method: 'PATCH' }),
+    post: (options) => request({ ...options, method: 'POST' }),
+    put: (options) => request({ ...options, method: 'PUT' }),
+    request,
+    setConfig,
+    trace: (options) => request({ ...options, method: 'TRACE' }),
+  };
+};

examples/openapi-ts-fetch/src/client/client/index.ts

···
+export type { Auth } from '../core/auth';
+export type { QuerySerializerOptions } from '../core/bodySerializer';
+export {
+  formDataBodySerializer,
+  jsonBodySerializer,
+  urlSearchParamsBodySerializer,
+} from '../core/bodySerializer';
+export { buildClientParams } from '../core/params';
+export { createClient } from './client';
+export type {
+  Client,
+  ClientOptions,
+  Config,
+  CreateClientConfig,
+  Options,
+  OptionsLegacyParser,
+  RequestOptions,
+  RequestResult,
+  ResponseStyle,
+  TDataShape,
+} from './types';
+export { createConfig, mergeHeaders } from './utils';

examples/openapi-ts-fetch/src/client/client/types.ts

···
+import type { Auth } from '../core/auth';
+import type { Client as CoreClient, Config as CoreConfig } from '../core/types';
+import type { Middleware } from './utils';
+
+export type ResponseStyle = 'data' | 'fields';
+
+export interface Config<T extends ClientOptions = ClientOptions>
+  extends Omit<RequestInit, 'body' | 'headers' | 'method'>,
+    CoreConfig {
+  /**
+   * Base URL for all requests made by this client.
+   */
+  baseUrl?: T['baseUrl'];
+  /**
+   * Fetch API implementation. You can use this option to provide a custom
+   * fetch instance.
+   *
+   * @default globalThis.fetch
+   */
+  fetch?: (request: Request) => ReturnType<typeof fetch>;
+  /**
+   * Please don't use the Fetch client for Next.js applications. The `next`
+   * options won't have any effect.
+   *
+   * Install {@link https://www.npmjs.com/package/@hey-api/client-next `@hey-api/client-next`} instead.
+   */
+  next?: never;
+  /**
+   * Return the response data parsed in a specified format. By default, `auto`
+   * will infer the appropriate method from the `Content-Type` response header.
+   * You can override this behavior with any of the {@link Body} methods.
+   * Select `stream` if you don't want to parse response data at all.
+   *
+   * @default 'auto'
+   */
+  parseAs?: Exclude<keyof Body, 'body' | 'bodyUsed'> | 'auto' | 'stream';
+  /**
+   * Should we return only data or multiple fields (data, error, response, etc.)?
+   *
+   * @default 'fields'
+   */
+  responseStyle?: ResponseStyle;
+  /**
+   * Throw an error instead of returning it in the response?
+   *
+   * @default false
+   */
+  throwOnError?: T['throwOnError'];
+}
+
+export interface RequestOptions<
+  TResponseStyle extends ResponseStyle = 'fields',
+  ThrowOnError extends boolean = boolean,
+  Url extends string = string,
+> extends Config<{
+    responseStyle: TResponseStyle;
+    throwOnError: ThrowOnError;
+  }> {
+  /**
+   * Any body that you want to add to your request.
+   *
+   * {@link https://developer.mozilla.org/docs/Web/API/fetch#body}
+   */
+  body?: unknown;
+  path?: Record<string, unknown>;
+  query?: Record<string, unknown>;
+  /**
+   * Security mechanism(s) to use for the request.
+   */
+  security?: ReadonlyArray<Auth>;
+  url: Url;
+}
+
+export type RequestResult<
+  TData = unknown,
+  TError = unknown,
+  ThrowOnError extends boolean = boolean,
+  TResponseStyle extends ResponseStyle = 'fields',
+> = ThrowOnError extends true
+  ? Promise<
+      TResponseStyle extends 'data'
+        ? TData extends Record<string, unknown>
+          ? TData[keyof TData]
+          : TData
+        : {
+            data: TData extends Record<string, unknown>
+              ? TData[keyof TData]
+              : TData;
+            request: Request;
+            response: Response;
+          }
+    >
+  : Promise<
+      TResponseStyle extends 'data'
+        ?
+            | (TData extends Record<string, unknown>
+                ? TData[keyof TData]
+                : TData)
+            | undefined
+        : (
+            | {
+                data: TData extends Record<string, unknown>
+                  ? TData[keyof TData]
+                  : TData;
+                error: undefined;
+              }
+            | {
+                data: undefined;
+                error: TError extends Record<string, unknown>
+                  ? TError[keyof TError]
+                  : TError;
+              }
+          ) & {
+            request: Request;
+            response: Response;
+          }
+    >;
+
+export interface ClientOptions {
+  baseUrl?: string;
+  responseStyle?: ResponseStyle;
+  throwOnError?: boolean;
+}
+
+type MethodFn = <
+  TData = unknown,
+  TError = unknown,
+  ThrowOnError extends boolean = false,
+  TResponseStyle extends ResponseStyle = 'fields',
+>(
+  options: Omit<RequestOptions<TResponseStyle, ThrowOnError>, 'method'>,
+) => RequestResult<TData, TError, ThrowOnError, TResponseStyle>;
+
+type RequestFn = <
+  TData = unknown,
+  TError = unknown,
+  ThrowOnError extends boolean = false,
+  TResponseStyle extends ResponseStyle = 'fields',
+>(
+  options: Omit<RequestOptions<TResponseStyle, ThrowOnError>, 'method'> &
+    Pick<Required<RequestOptions<TResponseStyle, ThrowOnError>>, 'method'>,
+) => RequestResult<TData, TError, ThrowOnError, TResponseStyle>;
+
+type BuildUrlFn = <
+  TData extends {
+    body?: unknown;
+    path?: Record<string, unknown>;
+    query?: Record<string, unknown>;
+    url: string;
+  },
+>(
+  options: Pick<TData, 'url'> & Options<TData>,
+) => string;
+
+export type Client = CoreClient<RequestFn, Config, MethodFn, BuildUrlFn> & {
+  interceptors: Middleware<Request, Response, unknown, RequestOptions>;
+};
+
+/**
+ * The `createClientConfig()` function will be called on client initialization
+ * and the returned object will become the client's initial configuration.
+ *
+ * You may want to initialize your client this way instead of calling
+ * `setConfig()`. This is useful for example if you're using Next.js
+ * to ensure your client always has the correct values.
+ */
+export type CreateClientConfig<T extends ClientOptions = ClientOptions> = (
+  override?: Config<ClientOptions & T>,
+) => Config<Required<ClientOptions> & T>;
+
+export interface TDataShape {
+  body?: unknown;
+  headers?: unknown;
+  path?: unknown;
+  query?: unknown;
+  url: string;
+}
+
+type OmitKeys<T, K> = Pick<T, Exclude<keyof T, K>>;
+
+export type Options<
+  TData extends TDataShape = TDataShape,
+  ThrowOnError extends boolean = boolean,
+  TResponseStyle extends ResponseStyle = 'fields',
+> = OmitKeys<
+  RequestOptions<TResponseStyle, ThrowOnError>,
+  'body' | 'path' | 'query' | 'url'
+> &
+  Omit<TData, 'url'>;
+
+export type OptionsLegacyParser<
+  TData = unknown,
+  ThrowOnError extends boolean = boolean,
+  TResponseStyle extends ResponseStyle = 'fields',
+> = TData extends { body?: any }
+  ? TData extends { headers?: any }
+    ? OmitKeys<
+        RequestOptions<TResponseStyle, ThrowOnError>,
+        'body' | 'headers' | 'url'
+      > &
+        TData
+    : OmitKeys<RequestOptions<TResponseStyle, ThrowOnError>, 'body' | 'url'> &
+        TData &
+        Pick<RequestOptions<TResponseStyle, ThrowOnError>, 'headers'>
+  : TData extends { headers?: any }
+    ? OmitKeys<
+        RequestOptions<TResponseStyle, ThrowOnError>,
+        'headers' | 'url'
+      > &
+        TData &
+        Pick<RequestOptions<TResponseStyle, ThrowOnError>, 'body'>
+    : OmitKeys<RequestOptions<TResponseStyle, ThrowOnError>, 'url'> & TData;

examples/openapi-ts-fetch/src/client/client/utils.ts

···
+import { getAuthToken } from '../core/auth';
+import type {
+  QuerySerializer,
+  QuerySerializerOptions,
+} from '../core/bodySerializer';
+import { jsonBodySerializer } from '../core/bodySerializer';
+import {
+  serializeArrayParam,
+  serializeObjectParam,
+  serializePrimitiveParam,
+} from '../core/pathSerializer';
+import type { Client, ClientOptions, Config, RequestOptions } from './types';
+
+interface PathSerializer {
+  path: Record<string, unknown>;
+  url: string;
+}
+
+const PATH_PARAM_RE = /\{[^{}]+\}/g;
+
+type ArrayStyle = 'form' | 'spaceDelimited' | 'pipeDelimited';
+type MatrixStyle = 'label' | 'matrix' | 'simple';
+type ArraySeparatorStyle = ArrayStyle | MatrixStyle;
+
+const defaultPathSerializer = ({ path, url: _url }: PathSerializer) => {
+  let url = _url;
+  const matches = _url.match(PATH_PARAM_RE);
+  if (matches) {
+    for (const match of matches) {
+      let explode = false;
+      let name = match.substring(1, match.length - 1);
+      let style: ArraySeparatorStyle = 'simple';
+
+      if (name.endsWith('*')) {
+        explode = true;
+        name = name.substring(0, name.length - 1);
+      }
+
+      if (name.startsWith('.')) {
+        name = name.substring(1);
+        style = 'label';
+      } else if (name.startsWith(';')) {
+        name = name.substring(1);
+        style = 'matrix';
+      }
+
+      const value = path[name];
+
+      if (value === undefined || value === null) {
+        continue;
+      }
+
+      if (Array.isArray(value)) {
+        url = url.replace(
+          match,
+          serializeArrayParam({ explode, name, style, value }),
+        );
+        continue;
+      }
+
+      if (typeof value === 'object') {
+        url = url.replace(
+          match,
+          serializeObjectParam({
+            explode,
+            name,
+            style,
+            value: value as Record<string, unknown>,
+            valueOnly: true,
+          }),
+        );
+        continue;
+      }
+
+      if (style === 'matrix') {
+        url = url.replace(
+          match,
+          `;${serializePrimitiveParam({
+            name,
+            value: value as string,
+          })}`,
+        );
+        continue;
+      }
+
+      const replaceValue = encodeURIComponent(
+        style === 'label' ? `.${value as string}` : (value as string),
+      );
+      url = url.replace(match, replaceValue);
+    }
+  }
+  return url;
+};
+
+export const createQuerySerializer = <T = unknown>({
+  allowReserved,
+  array,
+  object,
+}: QuerySerializerOptions = {}) => {
+  const querySerializer = (queryParams: T) => {
+    const search: string[] = [];
+    if (queryParams && typeof queryParams === 'object') {
+      for (const name in queryParams) {
+        const value = queryParams[name];
+
+        if (value === undefined || value === null) {
+          continue;
+        }
+
+        if (Array.isArray(value)) {
+          const serializedArray = serializeArrayParam({
+            allowReserved,
+            explode: true,
+            name,
+            style: 'form',
+            value,
+            ...array,
+          });
+          if (serializedArray) search.push(serializedArray);
+        } else if (typeof value === 'object') {
+          const serializedObject = serializeObjectParam({
+            allowReserved,
+            explode: true,
+            name,
+            style: 'deepObject',
+            value: value as Record<string, unknown>,
+            ...object,
+          });
+          if (serializedObject) search.push(serializedObject);
+        } else {
+          const serializedPrimitive = serializePrimitiveParam({
+            allowReserved,
+            name,
+            value: value as string,
+          });
+          if (serializedPrimitive) search.push(serializedPrimitive);
+        }
+      }
+    }
+    return search.join('&');
+  };
+  return querySerializer;
+};
+
+/**
+ * Infers parseAs value from provided Content-Type header.
+ */
+export const getParseAs = (
+  contentType: string | null,
+): Exclude<Config['parseAs'], 'auto'> => {
+  if (!contentType) {
+    // If no Content-Type header is provided, the best we can do is return the raw response body,
+    // which is effectively the same as the 'stream' option.
+    return 'stream';
+  }
+
+  const cleanContent = contentType.split(';')[0]?.trim();
+
+  if (!cleanContent) {
+    return;
+  }
+
+  if (
+    cleanContent.startsWith('application/json') ||
+    cleanContent.endsWith('+json')
+  ) {
+    return 'json';
+  }
+
+  if (cleanContent === 'multipart/form-data') {
+    return 'formData';
+  }
+
+  if (
+    ['application/', 'audio/', 'image/', 'video/'].some((type) =>
+      cleanContent.startsWith(type),
+    )
+  ) {
+    return 'blob';
+  }
+
+  if (cleanContent.startsWith('text/')) {
+    return 'text';
+  }
+};
+
+export const setAuthParams = async ({
+  security,
+  ...options
+}: Pick<Required<RequestOptions>, 'security'> &
+  Pick<RequestOptions, 'auth' | 'query'> & {
+    headers: Headers;
+  }) => {
+  for (const auth of security) {
+    const token = await getAuthToken(auth, options.auth);
+
+    if (!token) {
+      continue;
+    }
+
+    const name = auth.name ?? 'Authorization';
+
+    switch (auth.in) {
+      case 'query':
+        if (!options.query) {
+          options.query = {};
+        }
+        options.query[name] = token;
+        break;
+      case 'cookie':
+        options.headers.append('Cookie', `${name}=${token}`);
+        break;
+      case 'header':
+      default:
+        options.headers.set(name, token);
+        break;
+    }
+
+    return;
+  }
+};
+
+export const buildUrl: Client['buildUrl'] = (options) => {
+  const url = getUrl({
+    baseUrl: options.baseUrl as string,
+    path: options.path,
+    query: options.query,
+    querySerializer:
+      typeof options.querySerializer === 'function'
+        ? options.querySerializer
+        : createQuerySerializer(options.querySerializer),
+    url: options.url,
+  });
+  return url;
+};
+
+export const getUrl = ({
+  baseUrl,
+  path,
+  query,
+  querySerializer,
+  url: _url,
+}: {
+  baseUrl?: string;
+  path?: Record<string, unknown>;
+  query?: Record<string, unknown>;
+  querySerializer: QuerySerializer;
+  url: string;
+}) => {
+  const pathUrl = _url.startsWith('/') ? _url : `/${_url}`;
+  let url = (baseUrl ?? '') + pathUrl;
+  if (path) {
+    url = defaultPathSerializer({ path, url });
+  }
+  let search = query ? querySerializer(query) : '';
+  if (search.startsWith('?')) {
+    search = search.substring(1);
+  }
+  if (search) {
+    url += `?${search}`;
+  }
+  return url;
+};
+
+export const mergeConfigs = (a: Config, b: Config): Config => {
+  const config = { ...a, ...b };
+  if (config.baseUrl?.endsWith('/')) {
+    config.baseUrl = config.baseUrl.substring(0, config.baseUrl.length - 1);
+  }
+  config.headers = mergeHeaders(a.headers, b.headers);
+  return config;
+};
+
+export const mergeHeaders = (
+  ...headers: Array<Required<Config>['headers'] | undefined>
+): Headers => {
+  const mergedHeaders = new Headers();
+  for (const header of headers) {
+    if (!header || typeof header !== 'object') {
+      continue;
+    }
+
+    const iterator =
+      header instanceof Headers ? header.entries() : Object.entries(header);
+
+    for (const [key, value] of iterator) {
+      if (value === null) {
+        mergedHeaders.delete(key);
+      } else if (Array.isArray(value)) {
+        for (const v of value) {
+          mergedHeaders.append(key, v as string);
+        }
+      } else if (value !== undefined) {
+        // assume object headers are meant to be JSON stringified, i.e. their
+        // content value in OpenAPI specification is 'application/json'
+        mergedHeaders.set(
+          key,
+          typeof value === 'object' ? JSON.stringify(value) : (value as string),
+        );
+      }
+    }
+  }
+  return mergedHeaders;
+};
+
+type ErrInterceptor<Err, Res, Req, Options> = (
+  error: Err,
+  response: Res,
+  request: Req,
+  options: Options,
+) => Err | Promise<Err>;
+
+type ReqInterceptor<Req, Options> = (
+  request: Req,
+  options: Options,
+) => Req | Promise<Req>;
+
+type ResInterceptor<Res, Req, Options> = (
+  response: Res,
+  request: Req,
+  options: Options,
+) => Res | Promise<Res>;
+
+class Interceptors<Interceptor> {
+  _fns: (Interceptor | null)[];
+
+  constructor() {
+    this._fns = [];
+  }
+
+  clear() {
+    this._fns = [];
+  }
+
+  getInterceptorIndex(id: number | Interceptor): number {
+    if (typeof id === 'number') {
+      return this._fns[id] ? id : -1;
+    } else {
+      return this._fns.indexOf(id);
+    }
+  }
+  exists(id: number | Interceptor) {
+    const index = this.getInterceptorIndex(id);
+    return !!this._fns[index];
+  }
+
+  eject(id: number | Interceptor) {
+    const index = this.getInterceptorIndex(id);
+    if (this._fns[index]) {
+      this._fns[index] = null;
+    }
+  }
+
+  update(id: number | Interceptor, fn: Interceptor) {
+    const index = this.getInterceptorIndex(id);
+    if (this._fns[index]) {
+      this._fns[index] = fn;
+      return id;
+    } else {
+      return false;
+    }
+  }
+
+  use(fn: Interceptor) {
+    this._fns = [...this._fns, fn];
+    return this._fns.length - 1;
+  }
+}
+
+// `createInterceptors()` response, meant for external use as it does not
+// expose internals
+export interface Middleware<Req, Res, Err, Options> {
+  error: Pick<
+    Interceptors<ErrInterceptor<Err, Res, Req, Options>>,
+    'eject' | 'use'
+  >;
+  request: Pick<Interceptors<ReqInterceptor<Req, Options>>, 'eject' | 'use'>;
+  response: Pick<
+    Interceptors<ResInterceptor<Res, Req, Options>>,
+    'eject' | 'use'
+  >;
+}
+
+// do not add `Middleware` as return type so we can use _fns internally
+export const createInterceptors = <Req, Res, Err, Options>() => ({
+  error: new Interceptors<ErrInterceptor<Err, Res, Req, Options>>(),
+  request: new Interceptors<ReqInterceptor<Req, Options>>(),
+  response: new Interceptors<ResInterceptor<Res, Req, Options>>(),
+});
+
+const defaultQuerySerializer = createQuerySerializer({
+  allowReserved: false,
+  array: {
+    explode: true,
+    style: 'form',
+  },
+  object: {
+    explode: true,
+    style: 'deepObject',
+  },
+});
+
+const defaultHeaders = {
+  'Content-Type': 'application/json',
+};
+
+export const createConfig = <T extends ClientOptions = ClientOptions>(
+  override: Config<Omit<ClientOptions, keyof T> & T> = {},
+): Config<Omit<ClientOptions, keyof T> & T> => ({
+  ...jsonBodySerializer,
+  headers: defaultHeaders,
+  parseAs: 'auto',
+  querySerializer: defaultQuerySerializer,
+  ...override,
+});

examples/openapi-ts-fetch/src/client/core/auth.ts

···
+export type AuthToken = string | undefined;
+
+export interface Auth {
+  /**
+   * Which part of the request do we use to send the auth?
+   *
+   * @default 'header'
+   */
+  in?: 'header' | 'query' | 'cookie';
+  /**
+   * Header or query parameter name.
+   *
+   * @default 'Authorization'
+   */
+  name?: string;
+  scheme?: 'basic' | 'bearer';
+  type: 'apiKey' | 'http';
+}
+
+export const getAuthToken = async (
+  auth: Auth,
+  callback: ((auth: Auth) => Promise<AuthToken> | AuthToken) | AuthToken,
+): Promise<string | undefined> => {
+  const token =
+    typeof callback === 'function' ? await callback(auth) : callback;
+
+  if (!token) {
+    return;
+  }
+
+  if (auth.scheme === 'bearer') {
+    return `Bearer ${token}`;
+  }
+
+  if (auth.scheme === 'basic') {
+    return `Basic ${btoa(token)}`;
+  }
+
+  return token;
+};

examples/openapi-ts-fetch/src/client/core/bodySerializer.ts

···
+import type {
+  ArrayStyle,
+  ObjectStyle,
+  SerializerOptions,
+} from './pathSerializer';
+
+export type QuerySerializer = (query: Record<string, unknown>) => string;
+
+export type BodySerializer = (body: any) => any;
+
+export interface QuerySerializerOptions {
+  allowReserved?: boolean;
+  array?: SerializerOptions<ArrayStyle>;
+  object?: SerializerOptions<ObjectStyle>;
+}
+
+const serializeFormDataPair = (data: FormData, key: string, value: unknown) => {
+  if (typeof value === 'string' || value instanceof Blob) {
+    data.append(key, value);
+  } else {
+    data.append(key, JSON.stringify(value));
+  }
+};
+
+const serializeUrlSearchParamsPair = (
+  data: URLSearchParams,
+  key: string,
+  value: unknown,
+) => {
+  if (typeof value === 'string') {
+    data.append(key, value);
+  } else {
+    data.append(key, JSON.stringify(value));
+  }
+};
+
+export const formDataBodySerializer = {
+  bodySerializer: <T extends Record<string, any> | Array<Record<string, any>>>(
+    body: T,
+  ) => {
+    const data = new FormData();
+
+    Object.entries(body).forEach(([key, value]) => {
+      if (value === undefined || value === null) {
+        return;
+      }
+      if (Array.isArray(value)) {
+        value.forEach((v) => serializeFormDataPair(data, key, v));
+      } else {
+        serializeFormDataPair(data, key, value);
+      }
+    });
+
+    return data;
+  },
+};
+
+export const jsonBodySerializer = {
+  bodySerializer: <T>(body: T) =>
+    JSON.stringify(body, (key, value) =>
+      typeof value === 'bigint' ? value.toString() : value,
+    ),
+};
+
+export const urlSearchParamsBodySerializer = {
+  bodySerializer: <T extends Record<string, any> | Array<Record<string, any>>>(
+    body: T,
+  ) => {
+    const data = new URLSearchParams();
+
+    Object.entries(body).forEach(([key, value]) => {
+      if (value === undefined || value === null) {
+        return;
+      }
+      if (Array.isArray(value)) {
+        value.forEach((v) => serializeUrlSearchParamsPair(data, key, v));
+      } else {
+        serializeUrlSearchParamsPair(data, key, value);
+      }
+    });
+
+    return data.toString();
+  },
+};

examples/openapi-ts-fetch/src/client/core/params.ts

···
+type Slot = 'body' | 'headers' | 'path' | 'query';
+
+export type Field =
+  | {
+      in: Exclude<Slot, 'body'>;
+      key: string;
+      map?: string;
+    }
+  | {
+      in: Extract<Slot, 'body'>;
+      key?: string;
+      map?: string;
+    };
+
+export interface Fields {
+  allowExtra?: Partial<Record<Slot, boolean>>;
+  args?: ReadonlyArray<Field>;
+}
+
+export type FieldsConfig = ReadonlyArray<Field | Fields>;
+
+const extraPrefixesMap: Record<string, Slot> = {
+  $body_: 'body',
+  $headers_: 'headers',
+  $path_: 'path',
+  $query_: 'query',
+};
+const extraPrefixes = Object.entries(extraPrefixesMap);
+
+type KeyMap = Map<
+  string,
+  {
+    in: Slot;
+    map?: string;
+  }
+>;
+
+const buildKeyMap = (fields: FieldsConfig, map?: KeyMap): KeyMap => {
+  if (!map) {
+    map = new Map();
+  }
+
+  for (const config of fields) {
+    if ('in' in config) {
+      if (config.key) {
+        map.set(config.key, {
+          in: config.in,
+          map: config.map,
+        });
+      }
+    } else if (config.args) {
+      buildKeyMap(config.args, map);
+    }
+  }
+
+  return map;
+};
+
+interface Params {
+  body: unknown;
+  headers: Record<string, unknown>;
+  path: Record<string, unknown>;
+  query: Record<string, unknown>;
+}
+
+const stripEmptySlots = (params: Params) => {
+  for (const [slot, value] of Object.entries(params)) {
+    if (value && typeof value === 'object' && !Object.keys(value).length) {
+      delete params[slot as Slot];
+    }
+  }
+};
+
+export const buildClientParams = (
+  args: ReadonlyArray<unknown>,
+  fields: FieldsConfig,
+) => {
+  const params: Params = {
+    body: {},
+    headers: {},
+    path: {},
+    query: {},
+  };
+
+  const map = buildKeyMap(fields);
+
+  let config: FieldsConfig[number] | undefined;
+
+  for (const [index, arg] of args.entries()) {
+    if (fields[index]) {
+      config = fields[index];
+    }
+
+    if (!config) {
+      continue;
+    }
+
+    if ('in' in config) {
+      if (config.key) {
+        const field = map.get(config.key)!;
+        const name = field.map || config.key;
+        (params[field.in] as Record<string, unknown>)[name] = arg;
+      } else {
+        params.body = arg;
+      }
+    } else {
+      for (const [key, value] of Object.entries(arg ?? {})) {
+        const field = map.get(key);
+
+        if (field) {
+          const name = field.map || key;
+          (params[field.in] as Record<string, unknown>)[name] = value;
+        } else {
+          const extra = extraPrefixes.find(([prefix]) =>
+            key.startsWith(prefix),
+          );
+
+          if (extra) {
+            const [prefix, slot] = extra;
+            (params[slot] as Record<string, unknown>)[
+              key.slice(prefix.length)
+            ] = value;
+          } else {
+            for (const [slot, allowed] of Object.entries(
+              config.allowExtra ?? {},
+            )) {
+              if (allowed) {
+                (params[slot as Slot] as Record<string, unknown>)[key] = value;
+                break;
+              }
+            }
+          }
+        }
+      }
+    }
+  }
+
+  stripEmptySlots(params);
+
+  return params;
+};

examples/openapi-ts-fetch/src/client/core/pathSerializer.ts

···
+interface SerializeOptions<T>
+  extends SerializePrimitiveOptions,
+    SerializerOptions<T> {}
+
+interface SerializePrimitiveOptions {
+  allowReserved?: boolean;
+  name: string;
+}
+
+export interface SerializerOptions<T> {
+  /**
+   * @default true
+   */
+  explode: boolean;
+  style: T;
+}
+
+export type ArrayStyle = 'form' | 'spaceDelimited' | 'pipeDelimited';
+export type ArraySeparatorStyle = ArrayStyle | MatrixStyle;
+type MatrixStyle = 'label' | 'matrix' | 'simple';
+export type ObjectStyle = 'form' | 'deepObject';
+type ObjectSeparatorStyle = ObjectStyle | MatrixStyle;
+
+interface SerializePrimitiveParam extends SerializePrimitiveOptions {
+  value: string;
+}
+
+export const separatorArrayExplode = (style: ArraySeparatorStyle) => {
+  switch (style) {
+    case 'label':
+      return '.';
+    case 'matrix':
+      return ';';
+    case 'simple':
+      return ',';
+    default:
+      return '&';
+  }
+};
+
+export const separatorArrayNoExplode = (style: ArraySeparatorStyle) => {
+  switch (style) {
+    case 'form':
+      return ',';
+    case 'pipeDelimited':
+      return '|';
+    case 'spaceDelimited':
+      return '%20';
+    default:
+      return ',';
+  }
+};
+
+export const separatorObjectExplode = (style: ObjectSeparatorStyle) => {
+  switch (style) {
+    case 'label':
+      return '.';
+    case 'matrix':
+      return ';';
+    case 'simple':
+      return ',';
+    default:
+      return '&';
+  }
+};
+
+export const serializeArrayParam = ({
+  allowReserved,
+  explode,
+  name,
+  style,
+  value,
+}: SerializeOptions<ArraySeparatorStyle> & {
+  value: unknown[];
+}) => {
+  if (!explode) {
+    const joinedValues = (
+      allowReserved ? value : value.map((v) => encodeURIComponent(v as string))
+    ).join(separatorArrayNoExplode(style));
+    switch (style) {
+      case 'label':
+        return `.${joinedValues}`;
+      case 'matrix':
+        return `;${name}=${joinedValues}`;
+      case 'simple':
+        return joinedValues;
+      default:
+        return `${name}=${joinedValues}`;
+    }
+  }
+
+  const separator = separatorArrayExplode(style);
+  const joinedValues = value
+    .map((v) => {
+      if (style === 'label' || style === 'simple') {
+        return allowReserved ? v : encodeURIComponent(v as string);
+      }
+
+      return serializePrimitiveParam({
+        allowReserved,
+        name,
+        value: v as string,
+      });
+    })
+    .join(separator);
+  return style === 'label' || style === 'matrix'
+    ? separator + joinedValues
+    : joinedValues;
+};
+
+export const serializePrimitiveParam = ({
+  allowReserved,
+  name,
+  value,
+}: SerializePrimitiveParam) => {
+  if (value === undefined || value === null) {
+    return '';
+  }
+
+  if (typeof value === 'object') {
+    throw new Error(
+      'Deeply-nested arrays/objects aren’t supported. Provide your own `querySerializer()` to handle these.',
+    );
+  }
+
+  return `${name}=${allowReserved ? value : encodeURIComponent(value)}`;
+};
+
+export const serializeObjectParam = ({
+  allowReserved,
+  explode,
+  name,
+  style,
+  value,
+  valueOnly,
+}: SerializeOptions<ObjectSeparatorStyle> & {
+  value: Record<string, unknown> | Date;
+  valueOnly?: boolean;
+}) => {
+  if (value instanceof Date) {
+    return valueOnly ? value.toISOString() : `${name}=${value.toISOString()}`;
+  }
+
+  if (style !== 'deepObject' && !explode) {
+    let values: string[] = [];
+    Object.entries(value).forEach(([key, v]) => {
+      values = [
+        ...values,
+        key,
+        allowReserved ? (v as string) : encodeURIComponent(v as string),
+      ];
+    });
+    const joinedValues = values.join(',');
+    switch (style) {
+      case 'form':
+        return `${name}=${joinedValues}`;
+      case 'label':
+        return `.${joinedValues}`;
+      case 'matrix':
+        return `;${name}=${joinedValues}`;
+      default:
+        return joinedValues;
+    }
+  }
+
+  const separator = separatorObjectExplode(style);
+  const joinedValues = Object.entries(value)
+    .map(([key, v]) =>
+      serializePrimitiveParam({
+        allowReserved,
+        name: style === 'deepObject' ? `${name}[${key}]` : key,
+        value: v as string,
+      }),
+    )
+    .join(separator);
+  return style === 'label' || style === 'matrix'
+    ? separator + joinedValues
+    : joinedValues;
+};

examples/openapi-ts-fetch/src/client/core/types.ts

···
+import type { Auth, AuthToken } from './auth';
+import type {
+  BodySerializer,
+  QuerySerializer,
+  QuerySerializerOptions,
+} from './bodySerializer';
+
+export interface Client<
+  RequestFn = never,
+  Config = unknown,
+  MethodFn = never,
+  BuildUrlFn = never,
+> {
+  /**
+   * Returns the final request URL.
+   */
+  buildUrl: BuildUrlFn;
+  connect: MethodFn;
+  delete: MethodFn;
+  get: MethodFn;
+  getConfig: () => Config;
+  head: MethodFn;
+  options: MethodFn;
+  patch: MethodFn;
+  post: MethodFn;
+  put: MethodFn;
+  request: RequestFn;
+  setConfig: (config: Config) => Config;
+  trace: MethodFn;
+}
+
+export interface Config {
+  /**
+   * Auth token or a function returning auth token. The resolved value will be
+   * added to the request payload as defined by its `security` array.
+   */
+  auth?: ((auth: Auth) => Promise<AuthToken> | AuthToken) | AuthToken;
+  /**
+   * A function for serializing request body parameter. By default,
+   * {@link JSON.stringify()} will be used.
+   */
+  bodySerializer?: BodySerializer | null;
+  /**
+   * An object containing any HTTP headers that you want to pre-populate your
+   * `Headers` object with.
+   *
+   * {@link https://developer.mozilla.org/docs/Web/API/Headers/Headers#init See more}
+   */
+  headers?:
+    | RequestInit['headers']
+    | Record<
+        string,
+        | string
+        | number
+        | boolean
+        | (string | number | boolean)[]
+        | null
+        | undefined
+        | unknown
+      >;
+  /**
+   * The request method.
+   *
+   * {@link https://developer.mozilla.org/docs/Web/API/fetch#method See more}
+   */
+  method?:
+    | 'CONNECT'
+    | 'DELETE'
+    | 'GET'
+    | 'HEAD'
+    | 'OPTIONS'
+    | 'PATCH'
+    | 'POST'
+    | 'PUT'
+    | 'TRACE';
+  /**
+   * A function for serializing request query parameters. By default, arrays
+   * will be exploded in form style, objects will be exploded in deepObject
+   * style, and reserved characters are percent-encoded.
+   *
+   * This method will have no effect if the native `paramsSerializer()` Axios
+   * API function is used.
+   *
+   * {@link https://swagger.io/docs/specification/serialization/#query View examples}
+   */
+  querySerializer?: QuerySerializer | QuerySerializerOptions;
+  /**
+   * A function transforming response data before it's returned. This is useful
+   * for post-processing data, e.g. converting ISO strings into Date objects.
+   */
+  responseTransformer?: (data: unknown) => Promise<unknown>;
+  /**
+   * A function validating response data. This is useful if you want to ensure
+   * the response conforms to the desired shape, so it can be safely passed to
+   * the transformers and returned to the user.
+   */
+  responseValidator?: (data: unknown) => Promise<unknown>;
+}

examples/openapi-ts-fetch/src/client/sdk.gen.ts

···
 // This file is auto-generated by @hey-api/openapi-ts
 
-import type {
-  Client,
-  Options as ClientOptions,
-  TDataShape,
-} from '@hey-api/client-fetch';
-
+import type { Client, Options as ClientOptions, TDataShape } from './client';
 import { client as _heyApiClient } from './client.gen';
 import type {
   AddPetData,
···
     ...options,
     headers: {
       'Content-Type': 'application/json',
-      ...options?.headers,
+      ...options.headers,
     },
   });
 
···
     ...options,
     headers: {
       'Content-Type': 'application/json',
-      ...options?.headers,
+      ...options.headers,
     },
   });
 
···
     ...options,
     headers: {
       'Content-Type': 'application/octet-stream',
-      ...options?.headers,
+      ...options.headers,
     },
   });
 
···
     ...options,
     headers: {
       'Content-Type': 'application/json',
-      ...options?.headers,
+      ...options.headers,
     },
   });

examples/openapi-ts-next/package.json

···
     "start": "next start"
   },
   "dependencies": {
-    "@hey-api/client-next": "workspace:*",
     "next": "15.2.4",
     "react": "19.0.0",
     "react-dom": "19.0.0"

examples/openapi-ts-next/src/client/client.gen.ts

···
 // This file is auto-generated by @hey-api/openapi-ts
 
+import { createClientConfig } from '../hey-api';
 import {
   type ClientOptions as DefaultClientOptions,
   type Config,
   createClient,
   createConfig,
-} from '@hey-api/client-next';
-
-import { createClientConfig } from '../hey-api';
+} from './client';
 import type { ClientOptions } from './types.gen';
 
 /**

examples/openapi-ts-next/src/client/client/client.ts

···
+import type { Client, Config, RequestOptions } from './types';
+import {
+  buildUrl,
+  createConfig,
+  createInterceptors,
+  getParseAs,
+  mergeConfigs,
+  mergeHeaders,
+  setAuthParams,
+} from './utils';
+
+type ReqInit = Omit<RequestInit, 'body' | 'headers'> & {
+  body?: any;
+  headers: ReturnType<typeof mergeHeaders>;
+};
+
+export const createClient = (config: Config = {}): Client => {
+  let _config = mergeConfigs(createConfig(), config);
+
+  const getConfig = (): Config => ({ ..._config });
+
+  const setConfig = (config: Config): Config => {
+    _config = mergeConfigs(_config, config);
+    return getConfig();
+  };
+
+  const interceptors = createInterceptors<Response, unknown, RequestOptions>();
+
+  // @ts-expect-error
+  const request: Client['request'] = async (options) => {
+    const opts = {
+      ..._config,
+      ...options,
+      fetch: options.fetch ?? _config.fetch ?? globalThis.fetch,
+      headers: mergeHeaders(_config.headers, options.headers),
+    };
+
+    if (opts.security) {
+      await setAuthParams({
+        ...opts,
+        security: opts.security,
+      });
+    }
+
+    if (opts.body && opts.bodySerializer) {
+      opts.body = opts.bodySerializer(opts.body);
+    }
+
+    // remove Content-Type header if body is empty to avoid sending invalid requests
+    if (opts.body === undefined || opts.body === '') {
+      opts.headers.delete('Content-Type');
+    }
+
+    for (const fn of interceptors.request._fns) {
+      if (fn) {
+        await fn(opts);
+      }
+    }
+
+    const url = buildUrl(opts);
+    // fetch must be assigned here, otherwise it would throw the error:
+    // TypeError: Failed to execute 'fetch' on 'Window': Illegal invocation
+    const _fetch = opts.fetch!;
+    let response = await _fetch(url, {
+      ...opts,
+      body: opts.body as ReqInit['body'],
+    });
+
+    for (const fn of interceptors.response._fns) {
+      if (fn) {
+        response = await fn(response, opts);
+      }
+    }
+
+    const result = {
+      response,
+    };
+
+    if (response.ok) {
+      if (
+        response.status === 204 ||
+        response.headers.get('Content-Length') === '0'
+      ) {
+        return {
+          data: {},
+          ...result,
+        };
+      }
+
+      const parseAs =
+        (opts.parseAs === 'auto'
+          ? getParseAs(response.headers.get('Content-Type'))
+          : opts.parseAs) ?? 'json';
+
+      if (parseAs === 'stream') {
+        return {
+          data: response.body,
+          ...result,
+        };
+      }
+
+      let data = await response[parseAs]();
+      if (parseAs === 'json') {
+        if (opts.responseValidator) {
+          await opts.responseValidator(data);
+        }
+
+        if (opts.responseTransformer) {
+          data = await opts.responseTransformer(data);
+        }
+      }
+
+      return {
+        data,
+        ...result,
+      };
+    }
+
+    let error = await response.text();
+
+    try {
+      error = JSON.parse(error);
+    } catch {
+      // noop
+    }
+
+    let finalError = error;
+
+    for (const fn of interceptors.error._fns) {
+      if (fn) {
+        finalError = (await fn(error, response, opts)) as string;
+      }
+    }
+
+    finalError = finalError || ({} as string);
+
+    if (opts.throwOnError) {
+      throw finalError;
+    }
+
+    return {
+      error: finalError,
+      ...result,
+    };
+  };
+
+  return {
+    buildUrl,
+    connect: (options) => request({ ...options, method: 'CONNECT' }),
+    delete: (options) => request({ ...options, method: 'DELETE' }),
+    get: (options) => request({ ...options, method: 'GET' }),
+    getConfig,
+    head: (options) => request({ ...options, method: 'HEAD' }),
+    interceptors,
+    options: (options) => request({ ...options, method: 'OPTIONS' }),
+    patch: (options) => request({ ...options, method: 'PATCH' }),
+    post: (options) => request({ ...options, method: 'POST' }),
+    put: (options) => request({ ...options, method: 'PUT' }),
+    request,
+    setConfig,
+    trace: (options) => request({ ...options, method: 'TRACE' }),
+  };
+};

examples/openapi-ts-next/src/client/client/index.ts

···
+export type { Auth } from '../core/auth';
+export type { QuerySerializerOptions } from '../core/bodySerializer';
+export {
+  formDataBodySerializer,
+  jsonBodySerializer,
+  urlSearchParamsBodySerializer,
+} from '../core/bodySerializer';
+export { buildClientParams } from '../core/params';
+export { createClient } from './client';
+export type {
+  Client,
+  ClientOptions,
+  Config,
+  CreateClientConfig,
+  Options,
+  OptionsLegacyParser,
+  RequestOptions,
+  RequestResult,
+  TDataShape,
+} from './types';
+export { createConfig } from './utils';

examples/openapi-ts-next/src/client/client/types.ts

···
+import type { Auth } from '../core/auth';
+import type { Client as CoreClient, Config as CoreConfig } from '../core/types';
+import type { Middleware } from './utils';
+
+export interface Config<T extends ClientOptions = ClientOptions>
+  extends Omit<RequestInit, 'body' | 'headers' | 'method'>,
+    CoreConfig {
+  /**
+   * Base URL for all requests made by this client.
+   */
+  baseUrl?: T['baseUrl'];
+  /**
+   * Fetch API implementation. You can use this option to provide a custom
+   * fetch instance.
+   *
+   * @default globalThis.fetch
+   */
+  fetch?: typeof fetch;
+  /**
+   * Return the response data parsed in a specified format. By default, `auto`
+   * will infer the appropriate method from the `Content-Type` response header.
+   * You can override this behavior with any of the {@link Body} methods.
+   * Select `stream` if you don't want to parse response data at all.
+   *
+   * @default 'auto'
+   */
+  parseAs?: Exclude<keyof Body, 'body' | 'bodyUsed'> | 'auto' | 'stream';
+  /**
+   * Throw an error instead of returning it in the response?
+   *
+   * @default false
+   */
+  throwOnError?: T['throwOnError'];
+}
+
+export interface RequestOptions<
+  ThrowOnError extends boolean = boolean,
+  Url extends string = string,
+> extends Config<{
+    throwOnError: ThrowOnError;
+  }> {
+  /**
+   * Any body that you want to add to your request.
+   *
+   * {@link https://developer.mozilla.org/docs/Web/API/fetch#body}
+   */
+  body?: unknown;
+  path?: Record<string, unknown>;
+  query?: Record<string, unknown>;
+  /**
+   * Security mechanism(s) to use for the request.
+   */
+  security?: ReadonlyArray<Auth>;
+  url: Url;
+}
+
+export type RequestResult<
+  TData = unknown,
+  TError = unknown,
+  ThrowOnError extends boolean = boolean,
+> = ThrowOnError extends true
+  ? Promise<{
+      data: TData extends Record<string, unknown> ? TData[keyof TData] : TData;
+      response: Response;
+    }>
+  : Promise<
+      (
+        | {
+            data: TData extends Record<string, unknown>
+              ? TData[keyof TData]
+              : TData;
+            error: undefined;
+          }
+        | {
+            data: undefined;
+            error: TError extends Record<string, unknown>
+              ? TError[keyof TError]
+              : TError;
+          }
+      ) & {
+        response: Response;
+      }
+    >;
+
+export interface ClientOptions {
+  baseUrl?: string;
+  throwOnError?: boolean;
+}
+
+type MethodFn = <
+  TData = unknown,
+  TError = unknown,
+  ThrowOnError extends boolean = false,
+>(
+  options: Omit<RequestOptions<ThrowOnError>, 'method'>,
+) => RequestResult<TData, TError, ThrowOnError>;
+
+type RequestFn = <
+  TData = unknown,
+  TError = unknown,
+  ThrowOnError extends boolean = false,
+>(
+  options: Omit<RequestOptions<ThrowOnError>, 'method'> &
+    Pick<Required<RequestOptions<ThrowOnError>>, 'method'>,
+) => RequestResult<TData, TError, ThrowOnError>;
+
+type BuildUrlFn = <
+  TData extends {
+    body?: unknown;
+    path?: Record<string, unknown>;
+    query?: Record<string, unknown>;
+    url: string;
+  },
+>(
+  options: Pick<TData, 'url'> & Options<TData>,
+) => string;
+
+export type Client = CoreClient<RequestFn, Config, MethodFn, BuildUrlFn> & {
+  interceptors: Middleware<Response, unknown, RequestOptions>;
+};
+
+/**
+ * The `createClientConfig()` function will be called on client initialization
+ * and the returned object will become the client's initial configuration.
+ *
+ * You may want to initialize your client this way instead of calling
+ * `setConfig()`. This is useful for example if you're using Next.js
+ * to ensure your client always has the correct values.
+ */
+export type CreateClientConfig<T extends ClientOptions = ClientOptions> = (
+  override?: Config<ClientOptions & T>,
+) => Config<Required<ClientOptions> & T>;
+
+export interface TDataShape {
+  body?: unknown;
+  headers?: unknown;
+  path?: unknown;
+  query?: unknown;
+  url: string;
+}
+
+type OmitKeys<T, K> = Pick<T, Exclude<keyof T, K>>;
+
+export type Options<
+  TData extends TDataShape = TDataShape,
+  ThrowOnError extends boolean = boolean,
+> = OmitKeys<RequestOptions<ThrowOnError>, 'body' | 'path' | 'query' | 'url'> &
+  Omit<TData, 'url'>;
+
+export type OptionsLegacyParser<
+  TData = unknown,
+  ThrowOnError extends boolean = boolean,
+> = TData extends { body?: any }
+  ? TData extends { headers?: any }
+    ? OmitKeys<RequestOptions<ThrowOnError>, 'body' | 'headers' | 'url'> & TData
+    : OmitKeys<RequestOptions<ThrowOnError>, 'body' | 'url'> &
+        TData &
+        Pick<RequestOptions<ThrowOnError>, 'headers'>
+  : TData extends { headers?: any }
+    ? OmitKeys<RequestOptions<ThrowOnError>, 'headers' | 'url'> &
+        TData &
+        Pick<RequestOptions<ThrowOnError>, 'body'>
+    : OmitKeys<RequestOptions<ThrowOnError>, 'url'> & TData;

examples/openapi-ts-next/src/client/client/utils.ts

···
+import { getAuthToken } from '../core/auth';
+import type {
+  QuerySerializer,
+  QuerySerializerOptions,
+} from '../core/bodySerializer';
+import { jsonBodySerializer } from '../core/bodySerializer';
+import {
+  serializeArrayParam,
+  serializeObjectParam,
+  serializePrimitiveParam,
+} from '../core/pathSerializer';
+import type { Client, ClientOptions, Config, RequestOptions } from './types';
+
+interface PathSerializer {
+  path: Record<string, unknown>;
+  url: string;
+}
+
+const PATH_PARAM_RE = /\{[^{}]+\}/g;
+
+type ArrayStyle = 'form' | 'spaceDelimited' | 'pipeDelimited';
+type MatrixStyle = 'label' | 'matrix' | 'simple';
+type ArraySeparatorStyle = ArrayStyle | MatrixStyle;
+
+const defaultPathSerializer = ({ path, url: _url }: PathSerializer) => {
+  let url = _url;
+  const matches = _url.match(PATH_PARAM_RE);
+  if (matches) {
+    for (const match of matches) {
+      let explode = false;
+      let name = match.substring(1, match.length - 1);
+      let style: ArraySeparatorStyle = 'simple';
+
+      if (name.endsWith('*')) {
+        explode = true;
+        name = name.substring(0, name.length - 1);
+      }
+
+      if (name.startsWith('.')) {
+        name = name.substring(1);
+        style = 'label';
+      } else if (name.startsWith(';')) {
+        name = name.substring(1);
+        style = 'matrix';
+      }
+
+      const value = path[name];
+
+      if (value === undefined || value === null) {
+        continue;
+      }
+
+      if (Array.isArray(value)) {
+        url = url.replace(
+          match,
+          serializeArrayParam({ explode, name, style, value }),
+        );
+        continue;
+      }
+
+      if (typeof value === 'object') {
+        url = url.replace(
+          match,
+          serializeObjectParam({
+            explode,
+            name,
+            style,
+            value: value as Record<string, unknown>,
+            valueOnly: true,
+          }),
+        );
+        continue;
+      }
+
+      if (style === 'matrix') {
+        url = url.replace(
+          match,
+          `;${serializePrimitiveParam({
+            name,
+            value: value as string,
+          })}`,
+        );
+        continue;
+      }
+
+      const replaceValue = encodeURIComponent(
+        style === 'label' ? `.${value as string}` : (value as string),
+      );
+      url = url.replace(match, replaceValue);
+    }
+  }
+  return url;
+};
+
+export const createQuerySerializer = <T = unknown>({
+  allowReserved,
+  array,
+  object,
+}: QuerySerializerOptions = {}) => {
+  const querySerializer = (queryParams: T) => {
+    const search: string[] = [];
+    if (queryParams && typeof queryParams === 'object') {
+      for (const name in queryParams) {
+        const value = queryParams[name];
+
+        if (value === undefined || value === null) {
+          continue;
+        }
+
+        if (Array.isArray(value)) {
+          const serializedArray = serializeArrayParam({
+            allowReserved,
+            explode: true,
+            name,
+            style: 'form',
+            value,
+            ...array,
+          });
+          if (serializedArray) search.push(serializedArray);
+        } else if (typeof value === 'object') {
+          const serializedObject = serializeObjectParam({
+            allowReserved,
+            explode: true,
+            name,
+            style: 'deepObject',
+            value: value as Record<string, unknown>,
+            ...object,
+          });
+          if (serializedObject) search.push(serializedObject);
+        } else {
+          const serializedPrimitive = serializePrimitiveParam({
+            allowReserved,
+            name,
+            value: value as string,
+          });
+          if (serializedPrimitive) search.push(serializedPrimitive);
+        }
+      }
+    }
+    return search.join('&');
+  };
+  return querySerializer;
+};
+
+/**
+ * Infers parseAs value from provided Content-Type header.
+ */
+export const getParseAs = (
+  contentType: string | null,
+): Exclude<Config['parseAs'], 'auto'> => {
+  if (!contentType) {
+    // If no Content-Type header is provided, the best we can do is return the raw response body,
+    // which is effectively the same as the 'stream' option.
+    return 'stream';
+  }
+
+  const cleanContent = contentType.split(';')[0]?.trim();
+
+  if (!cleanContent) {
+    return;
+  }
+
+  if (
+    cleanContent.startsWith('application/json') ||
+    cleanContent.endsWith('+json')
+  ) {
+    return 'json';
+  }
+
+  if (cleanContent === 'multipart/form-data') {
+    return 'formData';
+  }
+
+  if (
+    ['application/', 'audio/', 'image/', 'video/'].some((type) =>
+      cleanContent.startsWith(type),
+    )
+  ) {
+    return 'blob';
+  }
+
+  if (cleanContent.startsWith('text/')) {
+    return 'text';
+  }
+};
+
+export const setAuthParams = async ({
+  security,
+  ...options
+}: Pick<Required<RequestOptions>, 'security'> &
+  Pick<RequestOptions, 'auth' | 'query'> & {
+    headers: Headers;
+  }) => {
+  for (const auth of security) {
+    const token = await getAuthToken(auth, options.auth);
+
+    if (!token) {
+      continue;
+    }
+
+    const name = auth.name ?? 'Authorization';
+
+    switch (auth.in) {
+      case 'query':
+        if (!options.query) {
+          options.query = {};
+        }
+        options.query[name] = token;
+        break;
+      case 'cookie':
+        options.headers.append('Cookie', `${name}=${token}`);
+        break;
+      case 'header':
+      default:
+        options.headers.set(name, token);
+        break;
+    }
+
+    return;
+  }
+};
+
+export const buildUrl: Client['buildUrl'] = (options) => {
+  const url = getUrl({
+    baseUrl: options.baseUrl as string,
+    path: options.path,
+    query: options.query,
+    querySerializer:
+      typeof options.querySerializer === 'function'
+        ? options.querySerializer
+        : createQuerySerializer(options.querySerializer),
+    url: options.url,
+  });
+  return url;
+};
+
+export const getUrl = ({
+  baseUrl,
+  path,
+  query,
+  querySerializer,
+  url: _url,
+}: {
+  baseUrl?: string;
+  path?: Record<string, unknown>;
+  query?: Record<string, unknown>;
+  querySerializer: QuerySerializer;
+  url: string;
+}) => {
+  const pathUrl = _url.startsWith('/') ? _url : `/${_url}`;
+  let url = (baseUrl ?? '') + pathUrl;
+  if (path) {
+    url = defaultPathSerializer({ path, url });
+  }
+  let search = query ? querySerializer(query) : '';
+  if (search.startsWith('?')) {
+    search = search.substring(1);
+  }
+  if (search) {
+    url += `?${search}`;
+  }
+  return url;
+};
+
+export const mergeConfigs = (a: Config, b: Config): Config => {
+  const config = { ...a, ...b };
+  if (config.baseUrl?.endsWith('/')) {
+    config.baseUrl = config.baseUrl.substring(0, config.baseUrl.length - 1);
+  }
+  config.headers = mergeHeaders(a.headers, b.headers);
+  return config;
+};
+
+export const mergeHeaders = (
+  ...headers: Array<Required<Config>['headers'] | undefined>
+): Headers => {
+  const mergedHeaders = new Headers();
+  for (const header of headers) {
+    if (!header || typeof header !== 'object') {
+      continue;
+    }
+
+    const iterator =
+      header instanceof Headers ? header.entries() : Object.entries(header);
+
+    for (const [key, value] of iterator) {
+      if (value === null) {
+        mergedHeaders.delete(key);
+      } else if (Array.isArray(value)) {
+        for (const v of value) {
+          mergedHeaders.append(key, v as string);
+        }
+      } else if (value !== undefined) {
+        // assume object headers are meant to be JSON stringified, i.e. their
+        // content value in OpenAPI specification is 'application/json'
+        mergedHeaders.set(
+          key,
+          typeof value === 'object' ? JSON.stringify(value) : (value as string),
+        );
+      }
+    }
+  }
+  return mergedHeaders;
+};
+
+type ErrInterceptor<Err, Res, Options> = (
+  error: Err,
+  response: Res,
+  options: Options,
+) => Err | Promise<Err>;
+
+type ReqInterceptor<Options> = (options: Options) => void | Promise<void>;
+
+type ResInterceptor<Res, Options> = (
+  response: Res,
+  options: Options,
+) => Res | Promise<Res>;
+
+class Interceptors<Interceptor> {
+  _fns: (Interceptor | null)[];
+
+  constructor() {
+    this._fns = [];
+  }
+
+  clear() {
+    this._fns = [];
+  }
+
+  getInterceptorIndex(id: number | Interceptor): number {
+    if (typeof id === 'number') {
+      return this._fns[id] ? id : -1;
+    } else {
+      return this._fns.indexOf(id);
+    }
+  }
+  exists(id: number | Interceptor) {
+    const index = this.getInterceptorIndex(id);
+    return !!this._fns[index];
+  }
+
+  eject(id: number | Interceptor) {
+    const index = this.getInterceptorIndex(id);
+    if (this._fns[index]) {
+      this._fns[index] = null;
+    }
+  }
+
+  update(id: number | Interceptor, fn: Interceptor) {
+    const index = this.getInterceptorIndex(id);
+    if (this._fns[index]) {
+      this._fns[index] = fn;
+      return id;
+    } else {
+      return false;
+    }
+  }
+
+  use(fn: Interceptor) {
+    this._fns = [...this._fns, fn];
+    return this._fns.length - 1;
+  }
+}
+
+// `createInterceptors()` response, meant for external use as it does not
+// expose internals
+export interface Middleware<Res, Err, Options> {
+  error: Pick<Interceptors<ErrInterceptor<Err, Res, Options>>, 'eject' | 'use'>;
+  request: Pick<Interceptors<ReqInterceptor<Options>>, 'eject' | 'use'>;
+  response: Pick<Interceptors<ResInterceptor<Res, Options>>, 'eject' | 'use'>;
+}
+
+// do not add `Middleware` as return type so we can use _fns internally
+export const createInterceptors = <Res, Err, Options>() => ({
+  error: new Interceptors<ErrInterceptor<Err, Res, Options>>(),
+  request: new Interceptors<ReqInterceptor<Options>>(),
+  response: new Interceptors<ResInterceptor<Res, Options>>(),
+});
+
+const defaultQuerySerializer = createQuerySerializer({
+  allowReserved: false,
+  array: {
+    explode: true,
+    style: 'form',
+  },
+  object: {
+    explode: true,
+    style: 'deepObject',
+  },
+});
+
+const defaultHeaders = {
+  'Content-Type': 'application/json',
+};
+
+export const createConfig = <T extends ClientOptions = ClientOptions>(
+  override: Config<Omit<ClientOptions, keyof T> & T> = {},
+): Config<Omit<ClientOptions, keyof T> & T> => ({
+  ...jsonBodySerializer,
+  headers: defaultHeaders,
+  parseAs: 'auto',
+  querySerializer: defaultQuerySerializer,
+  ...override,
+});

examples/openapi-ts-next/src/client/core/auth.ts

···
+export type AuthToken = string | undefined;
+
+export interface Auth {
+  /**
+   * Which part of the request do we use to send the auth?
+   *
+   * @default 'header'
+   */
+  in?: 'header' | 'query' | 'cookie';
+  /**
+   * Header or query parameter name.
+   *
+   * @default 'Authorization'
+   */
+  name?: string;
+  scheme?: 'basic' | 'bearer';
+  type: 'apiKey' | 'http';
+}
+
+export const getAuthToken = async (
+  auth: Auth,
+  callback: ((auth: Auth) => Promise<AuthToken> | AuthToken) | AuthToken,
+): Promise<string | undefined> => {
+  const token =
+    typeof callback === 'function' ? await callback(auth) : callback;
+
+  if (!token) {
+    return;
+  }
+
+  if (auth.scheme === 'bearer') {
+    return `Bearer ${token}`;
+  }
+
+  if (auth.scheme === 'basic') {
+    return `Basic ${btoa(token)}`;
+  }
+
+  return token;
+};

examples/openapi-ts-next/src/client/core/bodySerializer.ts

···
+import type {
+  ArrayStyle,
+  ObjectStyle,
+  SerializerOptions,
+} from './pathSerializer';
+
+export type QuerySerializer = (query: Record<string, unknown>) => string;
+
+export type BodySerializer = (body: any) => any;
+
+export interface QuerySerializerOptions {
+  allowReserved?: boolean;
+  array?: SerializerOptions<ArrayStyle>;
+  object?: SerializerOptions<ObjectStyle>;
+}
+
+const serializeFormDataPair = (data: FormData, key: string, value: unknown) => {
+  if (typeof value === 'string' || value instanceof Blob) {
+    data.append(key, value);
+  } else {
+    data.append(key, JSON.stringify(value));
+  }
+};
+
+const serializeUrlSearchParamsPair = (
+  data: URLSearchParams,
+  key: string,
+  value: unknown,
+) => {
+  if (typeof value === 'string') {
+    data.append(key, value);
+  } else {
+    data.append(key, JSON.stringify(value));
+  }
+};
+
+export const formDataBodySerializer = {
+  bodySerializer: <T extends Record<string, any> | Array<Record<string, any>>>(
+    body: T,
+  ) => {
+    const data = new FormData();
+
+    Object.entries(body).forEach(([key, value]) => {
+      if (value === undefined || value === null) {
+        return;
+      }
+      if (Array.isArray(value)) {
+        value.forEach((v) => serializeFormDataPair(data, key, v));
+      } else {
+        serializeFormDataPair(data, key, value);
+      }
+    });
+
+    return data;
+  },
+};
+
+export const jsonBodySerializer = {
+  bodySerializer: <T>(body: T) =>
+    JSON.stringify(body, (key, value) =>
+      typeof value === 'bigint' ? value.toString() : value,
+    ),
+};
+
+export const urlSearchParamsBodySerializer = {
+  bodySerializer: <T extends Record<string, any> | Array<Record<string, any>>>(
+    body: T,
+  ) => {
+    const data = new URLSearchParams();
+
+    Object.entries(body).forEach(([key, value]) => {
+      if (value === undefined || value === null) {
+        return;
+      }
+      if (Array.isArray(value)) {
+        value.forEach((v) => serializeUrlSearchParamsPair(data, key, v));
+      } else {
+        serializeUrlSearchParamsPair(data, key, value);
+      }
+    });
+
+    return data.toString();
+  },
+};

examples/openapi-ts-next/src/client/core/params.ts

···
+type Slot = 'body' | 'headers' | 'path' | 'query';
+
+export type Field =
+  | {
+      in: Exclude<Slot, 'body'>;
+      key: string;
+      map?: string;
+    }
+  | {
+      in: Extract<Slot, 'body'>;
+      key?: string;
+      map?: string;
+    };
+
+export interface Fields {
+  allowExtra?: Partial<Record<Slot, boolean>>;
+  args?: ReadonlyArray<Field>;
+}
+
+export type FieldsConfig = ReadonlyArray<Field | Fields>;
+
+const extraPrefixesMap: Record<string, Slot> = {
+  $body_: 'body',
+  $headers_: 'headers',
+  $path_: 'path',
+  $query_: 'query',
+};
+const extraPrefixes = Object.entries(extraPrefixesMap);
+
+type KeyMap = Map<
+  string,
+  {
+    in: Slot;
+    map?: string;
+  }
+>;
+
+const buildKeyMap = (fields: FieldsConfig, map?: KeyMap): KeyMap => {
+  if (!map) {
+    map = new Map();
+  }
+
+  for (const config of fields) {
+    if ('in' in config) {
+      if (config.key) {
+        map.set(config.key, {
+          in: config.in,
+          map: config.map,
+        });
+      }
+    } else if (config.args) {
+      buildKeyMap(config.args, map);
+    }
+  }
+
+  return map;
+};
+
+interface Params {
+  body: unknown;
+  headers: Record<string, unknown>;
+  path: Record<string, unknown>;
+  query: Record<string, unknown>;
+}
+
+const stripEmptySlots = (params: Params) => {
+  for (const [slot, value] of Object.entries(params)) {
+    if (value && typeof value === 'object' && !Object.keys(value).length) {
+      delete params[slot as Slot];
+    }
+  }
+};
+
+export const buildClientParams = (
+  args: ReadonlyArray<unknown>,
+  fields: FieldsConfig,
+) => {
+  const params: Params = {
+    body: {},
+    headers: {},
+    path: {},
+    query: {},
+  };
+
+  const map = buildKeyMap(fields);
+
+  let config: FieldsConfig[number] | undefined;
+
+  for (const [index, arg] of args.entries()) {
+    if (fields[index]) {
+      config = fields[index];
+    }
+
+    if (!config) {
+      continue;
+    }
+
+    if ('in' in config) {
+      if (config.key) {
+        const field = map.get(config.key)!;
+        const name = field.map || config.key;
+        (params[field.in] as Record<string, unknown>)[name] = arg;
+      } else {
+        params.body = arg;
+      }
+    } else {
+      for (const [key, value] of Object.entries(arg ?? {})) {
+        const field = map.get(key);
+
+        if (field) {
+          const name = field.map || key;
+          (params[field.in] as Record<string, unknown>)[name] = value;
+        } else {
+          const extra = extraPrefixes.find(([prefix]) =>
+            key.startsWith(prefix),
+          );
+
+          if (extra) {
+            const [prefix, slot] = extra;
+            (params[slot] as Record<string, unknown>)[
+              key.slice(prefix.length)
+            ] = value;
+          } else {
+            for (const [slot, allowed] of Object.entries(
+              config.allowExtra ?? {},
+            )) {
+              if (allowed) {
+                (params[slot as Slot] as Record<string, unknown>)[key] = value;
+                break;
+              }
+            }
+          }
+        }
+      }
+    }
+  }
+
+  stripEmptySlots(params);
+
+  return params;
+};

examples/openapi-ts-next/src/client/core/pathSerializer.ts

···
+interface SerializeOptions<T>
+  extends SerializePrimitiveOptions,
+    SerializerOptions<T> {}
+
+interface SerializePrimitiveOptions {
+  allowReserved?: boolean;
+  name: string;
+}
+
+export interface SerializerOptions<T> {
+  /**
+   * @default true
+   */
+  explode: boolean;
+  style: T;
+}
+
+export type ArrayStyle = 'form' | 'spaceDelimited' | 'pipeDelimited';
+export type ArraySeparatorStyle = ArrayStyle | MatrixStyle;
+type MatrixStyle = 'label' | 'matrix' | 'simple';
+export type ObjectStyle = 'form' | 'deepObject';
+type ObjectSeparatorStyle = ObjectStyle | MatrixStyle;
+
+interface SerializePrimitiveParam extends SerializePrimitiveOptions {
+  value: string;
+}
+
+export const separatorArrayExplode = (style: ArraySeparatorStyle) => {
+  switch (style) {
+    case 'label':
+      return '.';
+    case 'matrix':
+      return ';';
+    case 'simple':
+      return ',';
+    default:
+      return '&';
+  }
+};
+
+export const separatorArrayNoExplode = (style: ArraySeparatorStyle) => {
+  switch (style) {
+    case 'form':
+      return ',';
+    case 'pipeDelimited':
+      return '|';
+    case 'spaceDelimited':
+      return '%20';
+    default:
+      return ',';
+  }
+};
+
+export const separatorObjectExplode = (style: ObjectSeparatorStyle) => {
+  switch (style) {
+    case 'label':
+      return '.';
+    case 'matrix':
+      return ';';
+    case 'simple':
+      return ',';
+    default:
+      return '&';
+  }
+};
+
+export const serializeArrayParam = ({
+  allowReserved,
+  explode,
+  name,
+  style,
+  value,
+}: SerializeOptions<ArraySeparatorStyle> & {
+  value: unknown[];
+}) => {
+  if (!explode) {
+    const joinedValues = (
+      allowReserved ? value : value.map((v) => encodeURIComponent(v as string))
+    ).join(separatorArrayNoExplode(style));
+    switch (style) {
+      case 'label':
+        return `.${joinedValues}`;
+      case 'matrix':
+        return `;${name}=${joinedValues}`;
+      case 'simple':
+        return joinedValues;
+      default:
+        return `${name}=${joinedValues}`;
+    }
+  }
+
+  const separator = separatorArrayExplode(style);
+  const joinedValues = value
+    .map((v) => {
+      if (style === 'label' || style === 'simple') {
+        return allowReserved ? v : encodeURIComponent(v as string);
+      }
+
+      return serializePrimitiveParam({
+        allowReserved,
+        name,
+        value: v as string,
+      });
+    })
+    .join(separator);
+  return style === 'label' || style === 'matrix'
+    ? separator + joinedValues
+    : joinedValues;
+};
+
+export const serializePrimitiveParam = ({
+  allowReserved,
+  name,
+  value,
+}: SerializePrimitiveParam) => {
+  if (value === undefined || value === null) {
+    return '';
+  }
+
+  if (typeof value === 'object') {
+    throw new Error(
+      'Deeply-nested arrays/objects aren’t supported. Provide your own `querySerializer()` to handle these.',
+    );
+  }
+
+  return `${name}=${allowReserved ? value : encodeURIComponent(value)}`;
+};
+
+export const serializeObjectParam = ({
+  allowReserved,
+  explode,
+  name,
+  style,
+  value,
+  valueOnly,
+}: SerializeOptions<ObjectSeparatorStyle> & {
+  value: Record<string, unknown> | Date;
+  valueOnly?: boolean;
+}) => {
+  if (value instanceof Date) {
+    return valueOnly ? value.toISOString() : `${name}=${value.toISOString()}`;
+  }
+
+  if (style !== 'deepObject' && !explode) {
+    let values: string[] = [];
+    Object.entries(value).forEach(([key, v]) => {
+      values = [
+        ...values,
+        key,
+        allowReserved ? (v as string) : encodeURIComponent(v as string),
+      ];
+    });
+    const joinedValues = values.join(',');
+    switch (style) {
+      case 'form':
+        return `${name}=${joinedValues}`;
+      case 'label':
+        return `.${joinedValues}`;
+      case 'matrix':
+        return `;${name}=${joinedValues}`;
+      default:
+        return joinedValues;
+    }
+  }
+
+  const separator = separatorObjectExplode(style);
+  const joinedValues = Object.entries(value)
+    .map(([key, v]) =>
+      serializePrimitiveParam({
+        allowReserved,
+        name: style === 'deepObject' ? `${name}[${key}]` : key,
+        value: v as string,
+      }),
+    )
+    .join(separator);
+  return style === 'label' || style === 'matrix'
+    ? separator + joinedValues
+    : joinedValues;
+};

examples/openapi-ts-next/src/client/core/types.ts

···
+import type { Auth, AuthToken } from './auth';
+import type {
+  BodySerializer,
+  QuerySerializer,
+  QuerySerializerOptions,
+} from './bodySerializer';
+
+export interface Client<
+  RequestFn = never,
+  Config = unknown,
+  MethodFn = never,
+  BuildUrlFn = never,
+> {
+  /**
+   * Returns the final request URL.
+   */
+  buildUrl: BuildUrlFn;
+  connect: MethodFn;
+  delete: MethodFn;
+  get: MethodFn;
+  getConfig: () => Config;
+  head: MethodFn;
+  options: MethodFn;
+  patch: MethodFn;
+  post: MethodFn;
+  put: MethodFn;
+  request: RequestFn;
+  setConfig: (config: Config) => Config;
+  trace: MethodFn;
+}
+
+export interface Config {
+  /**
+   * Auth token or a function returning auth token. The resolved value will be
+   * added to the request payload as defined by its `security` array.
+   */
+  auth?: ((auth: Auth) => Promise<AuthToken> | AuthToken) | AuthToken;
+  /**
+   * A function for serializing request body parameter. By default,
+   * {@link JSON.stringify()} will be used.
+   */
+  bodySerializer?: BodySerializer | null;
+  /**
+   * An object containing any HTTP headers that you want to pre-populate your
+   * `Headers` object with.
+   *
+   * {@link https://developer.mozilla.org/docs/Web/API/Headers/Headers#init See more}
+   */
+  headers?:
+    | RequestInit['headers']
+    | Record<
+        string,
+        | string
+        | number
+        | boolean
+        | (string | number | boolean)[]
+        | null
+        | undefined
+        | unknown
+      >;
+  /**
+   * The request method.
+   *
+   * {@link https://developer.mozilla.org/docs/Web/API/fetch#method See more}
+   */
+  method?:
+    | 'CONNECT'
+    | 'DELETE'
+    | 'GET'
+    | 'HEAD'
+    | 'OPTIONS'
+    | 'PATCH'
+    | 'POST'
+    | 'PUT'
+    | 'TRACE';
+  /**
+   * A function for serializing request query parameters. By default, arrays
+   * will be exploded in form style, objects will be exploded in deepObject
+   * style, and reserved characters are percent-encoded.
+   *
+   * This method will have no effect if the native `paramsSerializer()` Axios
+   * API function is used.
+   *
+   * {@link https://swagger.io/docs/specification/serialization/#query View examples}
+   */
+  querySerializer?: QuerySerializer | QuerySerializerOptions;
+  /**
+   * A function transforming response data before it's returned. This is useful
+   * for post-processing data, e.g. converting ISO strings into Date objects.
+   */
+  responseTransformer?: (data: unknown) => Promise<unknown>;
+  /**
+   * A function validating response data. This is useful if you want to ensure
+   * the response conforms to the desired shape, so it can be safely passed to
+   * the transformers and returned to the user.
+   */
+  responseValidator?: (data: unknown) => Promise<unknown>;
+}

examples/openapi-ts-next/src/client/sdk.gen.ts

···
 // This file is auto-generated by @hey-api/openapi-ts
 
-import type {
-  Client,
-  Options as ClientOptions,
-  TDataShape,
-} from '@hey-api/client-next';
-
+import type { Client, Options as ClientOptions, TDataShape } from './client';
 import { client as _heyApiClient } from './client.gen';
 import type {
   AddPetData,
···
     ...options,
     headers: {
       'Content-Type': 'application/json',
-      ...options?.headers,
+      ...options.headers,
     },
   });
 
···
     ...options,
     headers: {
       'Content-Type': 'application/json',
-      ...options?.headers,
+      ...options.headers,
     },
   });
 
···
     ...options,
     headers: {
       'Content-Type': 'application/octet-stream',
-      ...options?.headers,
+      ...options.headers,
     },
   });
 
···
     ...options,
     headers: {
       'Content-Type': 'application/json',
-      ...options?.headers,
+      ...options.headers,
     },
   });

examples/openapi-ts-sample/package.json

···
     "typecheck": "tsc --noEmit"
   },
   "dependencies": {
-    "@hey-api/client-fetch": "workspace:*",
     "@radix-ui/react-form": "0.1.1",
     "@radix-ui/react-icons": "1.3.2",
     "@radix-ui/themes": "3.1.6",

examples/openapi-ts-sample/src/client/client.gen.ts

···
 // This file is auto-generated by @hey-api/openapi-ts
 
+import { createClientConfig } from '../hey-api';
 import {
   type ClientOptions as DefaultClientOptions,
   type Config,
   createClient,
   createConfig,
-} from '@hey-api/client-fetch';
-
-import { createClientConfig } from '../hey-api';
+} from './client';
 import type { ClientOptions } from './types.gen';
 
 /**

examples/openapi-ts-sample/src/client/client/client.ts

···
+import type { Client, Config, RequestOptions } from './types';
+import {
+  buildUrl,
+  createConfig,
+  createInterceptors,
+  getParseAs,
+  mergeConfigs,
+  mergeHeaders,
+  setAuthParams,
+} from './utils';
+
+type ReqInit = Omit<RequestInit, 'body' | 'headers'> & {
+  body?: any;
+  headers: ReturnType<typeof mergeHeaders>;
+};
+
+export const createClient = (config: Config = {}): Client => {
+  let _config = mergeConfigs(createConfig(), config);
+
+  const getConfig = (): Config => ({ ..._config });
+
+  const setConfig = (config: Config): Config => {
+    _config = mergeConfigs(_config, config);
+    return getConfig();
+  };
+
+  const interceptors = createInterceptors<
+    Request,
+    Response,
+    unknown,
+    RequestOptions
+  >();
+
+  const request: Client['request'] = async (options) => {
+    const opts = {
+      ..._config,
+      ...options,
+      fetch: options.fetch ?? _config.fetch ?? globalThis.fetch,
+      headers: mergeHeaders(_config.headers, options.headers),
+    };
+
+    if (opts.security) {
+      await setAuthParams({
+        ...opts,
+        security: opts.security,
+      });
+    }
+
+    if (opts.body && opts.bodySerializer) {
+      opts.body = opts.bodySerializer(opts.body);
+    }
+
+    // remove Content-Type header if body is empty to avoid sending invalid requests
+    if (opts.body === undefined || opts.body === '') {
+      opts.headers.delete('Content-Type');
+    }
+
+    const url = buildUrl(opts);
+    const requestInit: ReqInit = {
+      redirect: 'follow',
+      ...opts,
+    };
+
+    let request = new Request(url, requestInit);
+
+    for (const fn of interceptors.request._fns) {
+      if (fn) {
+        request = await fn(request, opts);
+      }
+    }
+
+    // fetch must be assigned here, otherwise it would throw the error:
+    // TypeError: Failed to execute 'fetch' on 'Window': Illegal invocation
+    const _fetch = opts.fetch!;
+    let response = await _fetch(request);
+
+    for (const fn of interceptors.response._fns) {
+      if (fn) {
+        response = await fn(response, request, opts);
+      }
+    }
+
+    const result = {
+      request,
+      response,
+    };
+
+    if (response.ok) {
+      if (
+        response.status === 204 ||
+        response.headers.get('Content-Length') === '0'
+      ) {
+        return opts.responseStyle === 'data'
+          ? {}
+          : {
+              data: {},
+              ...result,
+            };
+      }
+
+      const parseAs =
+        (opts.parseAs === 'auto'
+          ? getParseAs(response.headers.get('Content-Type'))
+          : opts.parseAs) ?? 'json';
+
+      if (parseAs === 'stream') {
+        return opts.responseStyle === 'data'
+          ? response.body
+          : {
+              data: response.body,
+              ...result,
+            };
+      }
+
+      let data = await response[parseAs]();
+      if (parseAs === 'json') {
+        if (opts.responseValidator) {
+          await opts.responseValidator(data);
+        }
+
+        if (opts.responseTransformer) {
+          data = await opts.responseTransformer(data);
+        }
+      }
+
+      return opts.responseStyle === 'data'
+        ? data
+        : {
+            data,
+            ...result,
+          };
+    }
+
+    let error = await response.text();
+
+    try {
+      error = JSON.parse(error);
+    } catch {
+      // noop
+    }
+
+    let finalError = error;
+
+    for (const fn of interceptors.error._fns) {
+      if (fn) {
+        finalError = (await fn(error, response, request, opts)) as string;
+      }
+    }
+
+    finalError = finalError || ({} as string);
+
+    if (opts.throwOnError) {
+      throw finalError;
+    }
+
+    // TODO: we probably want to return error and improve types
+    return opts.responseStyle === 'data'
+      ? undefined
+      : {
+          error: finalError,
+          ...result,
+        };
+  };
+
+  return {
+    buildUrl,
+    connect: (options) => request({ ...options, method: 'CONNECT' }),
+    delete: (options) => request({ ...options, method: 'DELETE' }),
+    get: (options) => request({ ...options, method: 'GET' }),
+    getConfig,
+    head: (options) => request({ ...options, method: 'HEAD' }),
+    interceptors,
+    options: (options) => request({ ...options, method: 'OPTIONS' }),
+    patch: (options) => request({ ...options, method: 'PATCH' }),
+    post: (options) => request({ ...options, method: 'POST' }),
+    put: (options) => request({ ...options, method: 'PUT' }),
+    request,
+    setConfig,
+    trace: (options) => request({ ...options, method: 'TRACE' }),
+  };
+};

examples/openapi-ts-sample/src/client/client/index.ts

···
+export type { Auth } from '../core/auth';
+export type { QuerySerializerOptions } from '../core/bodySerializer';
+export {
+  formDataBodySerializer,
+  jsonBodySerializer,
+  urlSearchParamsBodySerializer,
+} from '../core/bodySerializer';
+export { buildClientParams } from '../core/params';
+export { createClient } from './client';
+export type {
+  Client,
+  ClientOptions,
+  Config,
+  CreateClientConfig,
+  Options,
+  OptionsLegacyParser,
+  RequestOptions,
+  RequestResult,
+  ResponseStyle,
+  TDataShape,
+} from './types';
+export { createConfig, mergeHeaders } from './utils';

examples/openapi-ts-sample/src/client/client/types.ts

···
+import type { Auth } from '../core/auth';
+import type { Client as CoreClient, Config as CoreConfig } from '../core/types';
+import type { Middleware } from './utils';
+
+export type ResponseStyle = 'data' | 'fields';
+
+export interface Config<T extends ClientOptions = ClientOptions>
+  extends Omit<RequestInit, 'body' | 'headers' | 'method'>,
+    CoreConfig {
+  /**
+   * Base URL for all requests made by this client.
+   */
+  baseUrl?: T['baseUrl'];
+  /**
+   * Fetch API implementation. You can use this option to provide a custom
+   * fetch instance.
+   *
+   * @default globalThis.fetch
+   */
+  fetch?: (request: Request) => ReturnType<typeof fetch>;
+  /**
+   * Please don't use the Fetch client for Next.js applications. The `next`
+   * options won't have any effect.
+   *
+   * Install {@link https://www.npmjs.com/package/@hey-api/client-next `@hey-api/client-next`} instead.
+   */
+  next?: never;
+  /**
+   * Return the response data parsed in a specified format. By default, `auto`
+   * will infer the appropriate method from the `Content-Type` response header.
+   * You can override this behavior with any of the {@link Body} methods.
+   * Select `stream` if you don't want to parse response data at all.
+   *
+   * @default 'auto'
+   */
+  parseAs?: Exclude<keyof Body, 'body' | 'bodyUsed'> | 'auto' | 'stream';
+  /**
+   * Should we return only data or multiple fields (data, error, response, etc.)?
+   *
+   * @default 'fields'
+   */
+  responseStyle?: ResponseStyle;
+  /**
+   * Throw an error instead of returning it in the response?
+   *
+   * @default false
+   */
+  throwOnError?: T['throwOnError'];
+}
+
+export interface RequestOptions<
+  TResponseStyle extends ResponseStyle = 'fields',
+  ThrowOnError extends boolean = boolean,
+  Url extends string = string,
+> extends Config<{
+    responseStyle: TResponseStyle;
+    throwOnError: ThrowOnError;
+  }> {
+  /**
+   * Any body that you want to add to your request.
+   *
+   * {@link https://developer.mozilla.org/docs/Web/API/fetch#body}
+   */
+  body?: unknown;
+  path?: Record<string, unknown>;
+  query?: Record<string, unknown>;
+  /**
+   * Security mechanism(s) to use for the request.
+   */
+  security?: ReadonlyArray<Auth>;
+  url: Url;
+}
+
+export type RequestResult<
+  TData = unknown,
+  TError = unknown,
+  ThrowOnError extends boolean = boolean,
+  TResponseStyle extends ResponseStyle = 'fields',
+> = ThrowOnError extends true
+  ? Promise<
+      TResponseStyle extends 'data'
+        ? TData extends Record<string, unknown>
+          ? TData[keyof TData]
+          : TData
+        : {
+            data: TData extends Record<string, unknown>
+              ? TData[keyof TData]
+              : TData;
+            request: Request;
+            response: Response;
+          }
+    >
+  : Promise<
+      TResponseStyle extends 'data'
+        ?
+            | (TData extends Record<string, unknown>
+                ? TData[keyof TData]
+                : TData)
+            | undefined
+        : (
+            | {
+                data: TData extends Record<string, unknown>
+                  ? TData[keyof TData]
+                  : TData;
+                error: undefined;
+              }
+            | {
+                data: undefined;
+                error: TError extends Record<string, unknown>
+                  ? TError[keyof TError]
+                  : TError;
+              }
+          ) & {
+            request: Request;
+            response: Response;
+          }
+    >;
+
+export interface ClientOptions {
+  baseUrl?: string;
+  responseStyle?: ResponseStyle;
+  throwOnError?: boolean;
+}
+
+type MethodFn = <
+  TData = unknown,
+  TError = unknown,
+  ThrowOnError extends boolean = false,
+  TResponseStyle extends ResponseStyle = 'fields',
+>(
+  options: Omit<RequestOptions<TResponseStyle, ThrowOnError>, 'method'>,
+) => RequestResult<TData, TError, ThrowOnError, TResponseStyle>;
+
+type RequestFn = <
+  TData = unknown,
+  TError = unknown,
+  ThrowOnError extends boolean = false,
+  TResponseStyle extends ResponseStyle = 'fields',
+>(
+  options: Omit<RequestOptions<TResponseStyle, ThrowOnError>, 'method'> &
+    Pick<Required<RequestOptions<TResponseStyle, ThrowOnError>>, 'method'>,
+) => RequestResult<TData, TError, ThrowOnError, TResponseStyle>;
+
+type BuildUrlFn = <
+  TData extends {
+    body?: unknown;
+    path?: Record<string, unknown>;
+    query?: Record<string, unknown>;
+    url: string;
+  },
+>(
+  options: Pick<TData, 'url'> & Options<TData>,
+) => string;
+
+export type Client = CoreClient<RequestFn, Config, MethodFn, BuildUrlFn> & {
+  interceptors: Middleware<Request, Response, unknown, RequestOptions>;
+};
+
+/**
+ * The `createClientConfig()` function will be called on client initialization
+ * and the returned object will become the client's initial configuration.
+ *
+ * You may want to initialize your client this way instead of calling
+ * `setConfig()`. This is useful for example if you're using Next.js
+ * to ensure your client always has the correct values.
+ */
+export type CreateClientConfig<T extends ClientOptions = ClientOptions> = (
+  override?: Config<ClientOptions & T>,
+) => Config<Required<ClientOptions> & T>;
+
+export interface TDataShape {
+  body?: unknown;
+  headers?: unknown;
+  path?: unknown;
+  query?: unknown;
+  url: string;
+}
+
+type OmitKeys<T, K> = Pick<T, Exclude<keyof T, K>>;
+
+export type Options<
+  TData extends TDataShape = TDataShape,
+  ThrowOnError extends boolean = boolean,
+  TResponseStyle extends ResponseStyle = 'fields',
+> = OmitKeys<
+  RequestOptions<TResponseStyle, ThrowOnError>,
+  'body' | 'path' | 'query' | 'url'
+> &
+  Omit<TData, 'url'>;
+
+export type OptionsLegacyParser<
+  TData = unknown,
+  ThrowOnError extends boolean = boolean,
+  TResponseStyle extends ResponseStyle = 'fields',
+> = TData extends { body?: any }
+  ? TData extends { headers?: any }
+    ? OmitKeys<
+        RequestOptions<TResponseStyle, ThrowOnError>,
+        'body' | 'headers' | 'url'
+      > &
+        TData
+    : OmitKeys<RequestOptions<TResponseStyle, ThrowOnError>, 'body' | 'url'> &
+        TData &
+        Pick<RequestOptions<TResponseStyle, ThrowOnError>, 'headers'>
+  : TData extends { headers?: any }
+    ? OmitKeys<
+        RequestOptions<TResponseStyle, ThrowOnError>,
+        'headers' | 'url'
+      > &
+        TData &
+        Pick<RequestOptions<TResponseStyle, ThrowOnError>, 'body'>
+    : OmitKeys<RequestOptions<TResponseStyle, ThrowOnError>, 'url'> & TData;

examples/openapi-ts-sample/src/client/client/utils.ts

···
+import { getAuthToken } from '../core/auth';
+import type {
+  QuerySerializer,
+  QuerySerializerOptions,
+} from '../core/bodySerializer';
+import { jsonBodySerializer } from '../core/bodySerializer';
+import {
+  serializeArrayParam,
+  serializeObjectParam,
+  serializePrimitiveParam,
+} from '../core/pathSerializer';
+import type { Client, ClientOptions, Config, RequestOptions } from './types';
+
+interface PathSerializer {
+  path: Record<string, unknown>;
+  url: string;
+}
+
+const PATH_PARAM_RE = /\{[^{}]+\}/g;
+
+type ArrayStyle = 'form' | 'spaceDelimited' | 'pipeDelimited';
+type MatrixStyle = 'label' | 'matrix' | 'simple';
+type ArraySeparatorStyle = ArrayStyle | MatrixStyle;
+
+const defaultPathSerializer = ({ path, url: _url }: PathSerializer) => {
+  let url = _url;
+  const matches = _url.match(PATH_PARAM_RE);
+  if (matches) {
+    for (const match of matches) {
+      let explode = false;
+      let name = match.substring(1, match.length - 1);
+      let style: ArraySeparatorStyle = 'simple';
+
+      if (name.endsWith('*')) {
+        explode = true;
+        name = name.substring(0, name.length - 1);
+      }
+
+      if (name.startsWith('.')) {
+        name = name.substring(1);
+        style = 'label';
+      } else if (name.startsWith(';')) {
+        name = name.substring(1);
+        style = 'matrix';
+      }
+
+      const value = path[name];
+
+      if (value === undefined || value === null) {
+        continue;
+      }
+
+      if (Array.isArray(value)) {
+        url = url.replace(
+          match,
+          serializeArrayParam({ explode, name, style, value }),
+        );
+        continue;
+      }
+
+      if (typeof value === 'object') {
+        url = url.replace(
+          match,
+          serializeObjectParam({
+            explode,
+            name,
+            style,
+            value: value as Record<string, unknown>,
+            valueOnly: true,
+          }),
+        );
+        continue;
+      }
+
+      if (style === 'matrix') {
+        url = url.replace(
+          match,
+          `;${serializePrimitiveParam({
+            name,
+            value: value as string,
+          })}`,
+        );
+        continue;
+      }
+
+      const replaceValue = encodeURIComponent(
+        style === 'label' ? `.${value as string}` : (value as string),
+      );
+      url = url.replace(match, replaceValue);
+    }
+  }
+  return url;
+};
+
+export const createQuerySerializer = <T = unknown>({
+  allowReserved,
+  array,
+  object,
+}: QuerySerializerOptions = {}) => {
+  const querySerializer = (queryParams: T) => {
+    const search: string[] = [];
+    if (queryParams && typeof queryParams === 'object') {
+      for (const name in queryParams) {
+        const value = queryParams[name];
+
+        if (value === undefined || value === null) {
+          continue;
+        }
+
+        if (Array.isArray(value)) {
+          const serializedArray = serializeArrayParam({
+            allowReserved,
+            explode: true,
+            name,
+            style: 'form',
+            value,
+            ...array,
+          });
+          if (serializedArray) search.push(serializedArray);
+        } else if (typeof value === 'object') {
+          const serializedObject = serializeObjectParam({
+            allowReserved,
+            explode: true,
+            name,
+            style: 'deepObject',
+            value: value as Record<string, unknown>,
+            ...object,
+          });
+          if (serializedObject) search.push(serializedObject);
+        } else {
+          const serializedPrimitive = serializePrimitiveParam({
+            allowReserved,
+            name,
+            value: value as string,
+          });
+          if (serializedPrimitive) search.push(serializedPrimitive);
+        }
+      }
+    }
+    return search.join('&');
+  };
+  return querySerializer;
+};
+
+/**
+ * Infers parseAs value from provided Content-Type header.
+ */
+export const getParseAs = (
+  contentType: string | null,
+): Exclude<Config['parseAs'], 'auto'> => {
+  if (!contentType) {
+    // If no Content-Type header is provided, the best we can do is return the raw response body,
+    // which is effectively the same as the 'stream' option.
+    return 'stream';
+  }
+
+  const cleanContent = contentType.split(';')[0]?.trim();
+
+  if (!cleanContent) {
+    return;
+  }
+
+  if (
+    cleanContent.startsWith('application/json') ||
+    cleanContent.endsWith('+json')
+  ) {
+    return 'json';
+  }
+
+  if (cleanContent === 'multipart/form-data') {
+    return 'formData';
+  }
+
+  if (
+    ['application/', 'audio/', 'image/', 'video/'].some((type) =>
+      cleanContent.startsWith(type),
+    )
+  ) {
+    return 'blob';
+  }
+
+  if (cleanContent.startsWith('text/')) {
+    return 'text';
+  }
+};
+
+export const setAuthParams = async ({
+  security,
+  ...options
+}: Pick<Required<RequestOptions>, 'security'> &
+  Pick<RequestOptions, 'auth' | 'query'> & {
+    headers: Headers;
+  }) => {
+  for (const auth of security) {
+    const token = await getAuthToken(auth, options.auth);
+
+    if (!token) {
+      continue;
+    }
+
+    const name = auth.name ?? 'Authorization';
+
+    switch (auth.in) {
+      case 'query':
+        if (!options.query) {
+          options.query = {};
+        }
+        options.query[name] = token;
+        break;
+      case 'cookie':
+        options.headers.append('Cookie', `${name}=${token}`);
+        break;
+      case 'header':
+      default:
+        options.headers.set(name, token);
+        break;
+    }
+
+    return;
+  }
+};
+
+export const buildUrl: Client['buildUrl'] = (options) => {
+  const url = getUrl({
+    baseUrl: options.baseUrl as string,
+    path: options.path,
+    query: options.query,
+    querySerializer:
+      typeof options.querySerializer === 'function'
+        ? options.querySerializer
+        : createQuerySerializer(options.querySerializer),
+    url: options.url,
+  });
+  return url;
+};
+
+export const getUrl = ({
+  baseUrl,
+  path,
+  query,
+  querySerializer,
+  url: _url,
+}: {
+  baseUrl?: string;
+  path?: Record<string, unknown>;
+  query?: Record<string, unknown>;
+  querySerializer: QuerySerializer;
+  url: string;
+}) => {
+  const pathUrl = _url.startsWith('/') ? _url : `/${_url}`;
+  let url = (baseUrl ?? '') + pathUrl;
+  if (path) {
+    url = defaultPathSerializer({ path, url });
+  }
+  let search = query ? querySerializer(query) : '';
+  if (search.startsWith('?')) {
+    search = search.substring(1);
+  }
+  if (search) {
+    url += `?${search}`;
+  }
+  return url;
+};
+
+export const mergeConfigs = (a: Config, b: Config): Config => {
+  const config = { ...a, ...b };
+  if (config.baseUrl?.endsWith('/')) {
+    config.baseUrl = config.baseUrl.substring(0, config.baseUrl.length - 1);
+  }
+  config.headers = mergeHeaders(a.headers, b.headers);
+  return config;
+};
+
+export const mergeHeaders = (
+  ...headers: Array<Required<Config>['headers'] | undefined>
+): Headers => {
+  const mergedHeaders = new Headers();
+  for (const header of headers) {
+    if (!header || typeof header !== 'object') {
+      continue;
+    }
+
+    const iterator =
+      header instanceof Headers ? header.entries() : Object.entries(header);
+
+    for (const [key, value] of iterator) {
+      if (value === null) {
+        mergedHeaders.delete(key);
+      } else if (Array.isArray(value)) {
+        for (const v of value) {
+          mergedHeaders.append(key, v as string);
+        }
+      } else if (value !== undefined) {
+        // assume object headers are meant to be JSON stringified, i.e. their
+        // content value in OpenAPI specification is 'application/json'
+        mergedHeaders.set(
+          key,
+          typeof value === 'object' ? JSON.stringify(value) : (value as string),
+        );
+      }
+    }
+  }
+  return mergedHeaders;
+};
+
+type ErrInterceptor<Err, Res, Req, Options> = (
+  error: Err,
+  response: Res,
+  request: Req,
+  options: Options,
+) => Err | Promise<Err>;
+
+type ReqInterceptor<Req, Options> = (
+  request: Req,
+  options: Options,
+) => Req | Promise<Req>;
+
+type ResInterceptor<Res, Req, Options> = (
+  response: Res,
+  request: Req,
+  options: Options,
+) => Res | Promise<Res>;
+
+class Interceptors<Interceptor> {
+  _fns: (Interceptor | null)[];
+
+  constructor() {
+    this._fns = [];
+  }
+
+  clear() {
+    this._fns = [];
+  }
+
+  getInterceptorIndex(id: number | Interceptor): number {
+    if (typeof id === 'number') {
+      return this._fns[id] ? id : -1;
+    } else {
+      return this._fns.indexOf(id);
+    }
+  }
+  exists(id: number | Interceptor) {
+    const index = this.getInterceptorIndex(id);
+    return !!this._fns[index];
+  }
+
+  eject(id: number | Interceptor) {
+    const index = this.getInterceptorIndex(id);
+    if (this._fns[index]) {
+      this._fns[index] = null;
+    }
+  }
+
+  update(id: number | Interceptor, fn: Interceptor) {
+    const index = this.getInterceptorIndex(id);
+    if (this._fns[index]) {
+      this._fns[index] = fn;
+      return id;
+    } else {
+      return false;
+    }
+  }
+
+  use(fn: Interceptor) {
+    this._fns = [...this._fns, fn];
+    return this._fns.length - 1;
+  }
+}
+
+// `createInterceptors()` response, meant for external use as it does not
+// expose internals
+export interface Middleware<Req, Res, Err, Options> {
+  error: Pick<
+    Interceptors<ErrInterceptor<Err, Res, Req, Options>>,
+    'eject' | 'use'
+  >;
+  request: Pick<Interceptors<ReqInterceptor<Req, Options>>, 'eject' | 'use'>;
+  response: Pick<
+    Interceptors<ResInterceptor<Res, Req, Options>>,
+    'eject' | 'use'
+  >;
+}
+
+// do not add `Middleware` as return type so we can use _fns internally
+export const createInterceptors = <Req, Res, Err, Options>() => ({
+  error: new Interceptors<ErrInterceptor<Err, Res, Req, Options>>(),
+  request: new Interceptors<ReqInterceptor<Req, Options>>(),
+  response: new Interceptors<ResInterceptor<Res, Req, Options>>(),
+});
+
+const defaultQuerySerializer = createQuerySerializer({
+  allowReserved: false,
+  array: {
+    explode: true,
+    style: 'form',
+  },
+  object: {
+    explode: true,
+    style: 'deepObject',
+  },
+});
+
+const defaultHeaders = {
+  'Content-Type': 'application/json',
+};
+
+export const createConfig = <T extends ClientOptions = ClientOptions>(
+  override: Config<Omit<ClientOptions, keyof T> & T> = {},
+): Config<Omit<ClientOptions, keyof T> & T> => ({
+  ...jsonBodySerializer,
+  headers: defaultHeaders,
+  parseAs: 'auto',
+  querySerializer: defaultQuerySerializer,
+  ...override,
+});

examples/openapi-ts-sample/src/client/core/auth.ts

···
+export type AuthToken = string | undefined;
+
+export interface Auth {
+  /**
+   * Which part of the request do we use to send the auth?
+   *
+   * @default 'header'
+   */
+  in?: 'header' | 'query' | 'cookie';
+  /**
+   * Header or query parameter name.
+   *
+   * @default 'Authorization'
+   */
+  name?: string;
+  scheme?: 'basic' | 'bearer';
+  type: 'apiKey' | 'http';
+}
+
+export const getAuthToken = async (
+  auth: Auth,
+  callback: ((auth: Auth) => Promise<AuthToken> | AuthToken) | AuthToken,
+): Promise<string | undefined> => {
+  const token =
+    typeof callback === 'function' ? await callback(auth) : callback;
+
+  if (!token) {
+    return;
+  }
+
+  if (auth.scheme === 'bearer') {
+    return `Bearer ${token}`;
+  }
+
+  if (auth.scheme === 'basic') {
+    return `Basic ${btoa(token)}`;
+  }
+
+  return token;
+};

examples/openapi-ts-sample/src/client/core/bodySerializer.ts

···
+import type {
+  ArrayStyle,
+  ObjectStyle,
+  SerializerOptions,
+} from './pathSerializer';
+
+export type QuerySerializer = (query: Record<string, unknown>) => string;
+
+export type BodySerializer = (body: any) => any;
+
+export interface QuerySerializerOptions {
+  allowReserved?: boolean;
+  array?: SerializerOptions<ArrayStyle>;
+  object?: SerializerOptions<ObjectStyle>;
+}
+
+const serializeFormDataPair = (data: FormData, key: string, value: unknown) => {
+  if (typeof value === 'string' || value instanceof Blob) {
+    data.append(key, value);
+  } else {
+    data.append(key, JSON.stringify(value));
+  }
+};
+
+const serializeUrlSearchParamsPair = (
+  data: URLSearchParams,
+  key: string,
+  value: unknown,
+) => {
+  if (typeof value === 'string') {
+    data.append(key, value);
+  } else {
+    data.append(key, JSON.stringify(value));
+  }
+};
+
+export const formDataBodySerializer = {
+  bodySerializer: <T extends Record<string, any> | Array<Record<string, any>>>(
+    body: T,
+  ) => {
+    const data = new FormData();
+
+    Object.entries(body).forEach(([key, value]) => {
+      if (value === undefined || value === null) {
+        return;
+      }
+      if (Array.isArray(value)) {
+        value.forEach((v) => serializeFormDataPair(data, key, v));
+      } else {
+        serializeFormDataPair(data, key, value);
+      }
+    });
+
+    return data;
+  },
+};
+
+export const jsonBodySerializer = {
+  bodySerializer: <T>(body: T) =>
+    JSON.stringify(body, (key, value) =>
+      typeof value === 'bigint' ? value.toString() : value,
+    ),
+};
+
+export const urlSearchParamsBodySerializer = {
+  bodySerializer: <T extends Record<string, any> | Array<Record<string, any>>>(
+    body: T,
+  ) => {
+    const data = new URLSearchParams();
+
+    Object.entries(body).forEach(([key, value]) => {
+      if (value === undefined || value === null) {
+        return;
+      }
+      if (Array.isArray(value)) {
+        value.forEach((v) => serializeUrlSearchParamsPair(data, key, v));
+      } else {
+        serializeUrlSearchParamsPair(data, key, value);
+      }
+    });
+
+    return data.toString();
+  },
+};

examples/openapi-ts-sample/src/client/core/params.ts

···
+type Slot = 'body' | 'headers' | 'path' | 'query';
+
+export type Field =
+  | {
+      in: Exclude<Slot, 'body'>;
+      key: string;
+      map?: string;
+    }
+  | {
+      in: Extract<Slot, 'body'>;
+      key?: string;
+      map?: string;
+    };
+
+export interface Fields {
+  allowExtra?: Partial<Record<Slot, boolean>>;
+  args?: ReadonlyArray<Field>;
+}
+
+export type FieldsConfig = ReadonlyArray<Field | Fields>;
+
+const extraPrefixesMap: Record<string, Slot> = {
+  $body_: 'body',
+  $headers_: 'headers',
+  $path_: 'path',
+  $query_: 'query',
+};
+const extraPrefixes = Object.entries(extraPrefixesMap);
+
+type KeyMap = Map<
+  string,
+  {
+    in: Slot;
+    map?: string;
+  }
+>;
+
+const buildKeyMap = (fields: FieldsConfig, map?: KeyMap): KeyMap => {
+  if (!map) {
+    map = new Map();
+  }
+
+  for (const config of fields) {
+    if ('in' in config) {
+      if (config.key) {
+        map.set(config.key, {
+          in: config.in,
+          map: config.map,
+        });
+      }
+    } else if (config.args) {
+      buildKeyMap(config.args, map);
+    }
+  }
+
+  return map;
+};
+
+interface Params {
+  body: unknown;
+  headers: Record<string, unknown>;
+  path: Record<string, unknown>;
+  query: Record<string, unknown>;
+}
+
+const stripEmptySlots = (params: Params) => {
+  for (const [slot, value] of Object.entries(params)) {
+    if (value && typeof value === 'object' && !Object.keys(value).length) {
+      delete params[slot as Slot];
+    }
+  }
+};
+
+export const buildClientParams = (
+  args: ReadonlyArray<unknown>,
+  fields: FieldsConfig,
+) => {
+  const params: Params = {
+    body: {},
+    headers: {},
+    path: {},
+    query: {},
+  };
+
+  const map = buildKeyMap(fields);
+
+  let config: FieldsConfig[number] | undefined;
+
+  for (const [index, arg] of args.entries()) {
+    if (fields[index]) {
+      config = fields[index];
+    }
+
+    if (!config) {
+      continue;
+    }
+
+    if ('in' in config) {
+      if (config.key) {
+        const field = map.get(config.key)!;
+        const name = field.map || config.key;
+        (params[field.in] as Record<string, unknown>)[name] = arg;
+      } else {
+        params.body = arg;
+      }
+    } else {
+      for (const [key, value] of Object.entries(arg ?? {})) {
+        const field = map.get(key);
+
+        if (field) {
+          const name = field.map || key;
+          (params[field.in] as Record<string, unknown>)[name] = value;
+        } else {
+          const extra = extraPrefixes.find(([prefix]) =>
+            key.startsWith(prefix),
+          );
+
+          if (extra) {
+            const [prefix, slot] = extra;
+            (params[slot] as Record<string, unknown>)[
+              key.slice(prefix.length)
+            ] = value;
+          } else {
+            for (const [slot, allowed] of Object.entries(
+              config.allowExtra ?? {},
+            )) {
+              if (allowed) {
+                (params[slot as Slot] as Record<string, unknown>)[key] = value;
+                break;
+              }
+            }
+          }
+        }
+      }
+    }
+  }
+
+  stripEmptySlots(params);
+
+  return params;
+};

examples/openapi-ts-sample/src/client/core/pathSerializer.ts

···
+interface SerializeOptions<T>
+  extends SerializePrimitiveOptions,
+    SerializerOptions<T> {}
+
+interface SerializePrimitiveOptions {
+  allowReserved?: boolean;
+  name: string;
+}
+
+export interface SerializerOptions<T> {
+  /**
+   * @default true
+   */
+  explode: boolean;
+  style: T;
+}
+
+export type ArrayStyle = 'form' | 'spaceDelimited' | 'pipeDelimited';
+export type ArraySeparatorStyle = ArrayStyle | MatrixStyle;
+type MatrixStyle = 'label' | 'matrix' | 'simple';
+export type ObjectStyle = 'form' | 'deepObject';
+type ObjectSeparatorStyle = ObjectStyle | MatrixStyle;
+
+interface SerializePrimitiveParam extends SerializePrimitiveOptions {
+  value: string;
+}
+
+export const separatorArrayExplode = (style: ArraySeparatorStyle) => {
+  switch (style) {
+    case 'label':
+      return '.';
+    case 'matrix':
+      return ';';
+    case 'simple':
+      return ',';
+    default:
+      return '&';
+  }
+};
+
+export const separatorArrayNoExplode = (style: ArraySeparatorStyle) => {
+  switch (style) {
+    case 'form':
+      return ',';
+    case 'pipeDelimited':
+      return '|';
+    case 'spaceDelimited':
+      return '%20';
+    default:
+      return ',';
+  }
+};
+
+export const separatorObjectExplode = (style: ObjectSeparatorStyle) => {
+  switch (style) {
+    case 'label':
+      return '.';
+    case 'matrix':
+      return ';';
+    case 'simple':
+      return ',';
+    default:
+      return '&';
+  }
+};
+
+export const serializeArrayParam = ({
+  allowReserved,
+  explode,
+  name,
+  style,
+  value,
+}: SerializeOptions<ArraySeparatorStyle> & {
+  value: unknown[];
+}) => {
+  if (!explode) {
+    const joinedValues = (
+      allowReserved ? value : value.map((v) => encodeURIComponent(v as string))
+    ).join(separatorArrayNoExplode(style));
+    switch (style) {
+      case 'label':
+        return `.${joinedValues}`;
+      case 'matrix':
+        return `;${name}=${joinedValues}`;
+      case 'simple':
+        return joinedValues;
+      default:
+        return `${name}=${joinedValues}`;
+    }
+  }
+
+  const separator = separatorArrayExplode(style);
+  const joinedValues = value
+    .map((v) => {
+      if (style === 'label' || style === 'simple') {
+        return allowReserved ? v : encodeURIComponent(v as string);
+      }
+
+      return serializePrimitiveParam({
+        allowReserved,
+        name,
+        value: v as string,
+      });
+    })
+    .join(separator);
+  return style === 'label' || style === 'matrix'
+    ? separator + joinedValues
+    : joinedValues;
+};
+
+export const serializePrimitiveParam = ({
+  allowReserved,
+  name,
+  value,
+}: SerializePrimitiveParam) => {
+  if (value === undefined || value === null) {
+    return '';
+  }
+
+  if (typeof value === 'object') {
+    throw new Error(
+      'Deeply-nested arrays/objects aren’t supported. Provide your own `querySerializer()` to handle these.',
+    );
+  }
+
+  return `${name}=${allowReserved ? value : encodeURIComponent(value)}`;
+};
+
+export const serializeObjectParam = ({
+  allowReserved,
+  explode,
+  name,
+  style,
+  value,
+  valueOnly,
+}: SerializeOptions<ObjectSeparatorStyle> & {
+  value: Record<string, unknown> | Date;
+  valueOnly?: boolean;
+}) => {
+  if (value instanceof Date) {
+    return valueOnly ? value.toISOString() : `${name}=${value.toISOString()}`;
+  }
+
+  if (style !== 'deepObject' && !explode) {
+    let values: string[] = [];
+    Object.entries(value).forEach(([key, v]) => {
+      values = [
+        ...values,
+        key,
+        allowReserved ? (v as string) : encodeURIComponent(v as string),
+      ];
+    });
+    const joinedValues = values.join(',');
+    switch (style) {
+      case 'form':
+        return `${name}=${joinedValues}`;
+      case 'label':
+        return `.${joinedValues}`;
+      case 'matrix':
+        return `;${name}=${joinedValues}`;
+      default:
+        return joinedValues;
+    }
+  }
+
+  const separator = separatorObjectExplode(style);
+  const joinedValues = Object.entries(value)
+    .map(([key, v]) =>
+      serializePrimitiveParam({
+        allowReserved,
+        name: style === 'deepObject' ? `${name}[${key}]` : key,
+        value: v as string,
+      }),
+    )
+    .join(separator);
+  return style === 'label' || style === 'matrix'
+    ? separator + joinedValues
+    : joinedValues;
+};

examples/openapi-ts-sample/src/client/core/types.ts

···
+import type { Auth, AuthToken } from './auth';
+import type {
+  BodySerializer,
+  QuerySerializer,
+  QuerySerializerOptions,
+} from './bodySerializer';
+
+export interface Client<
+  RequestFn = never,
+  Config = unknown,
+  MethodFn = never,
+  BuildUrlFn = never,
+> {
+  /**
+   * Returns the final request URL.
+   */
+  buildUrl: BuildUrlFn;
+  connect: MethodFn;
+  delete: MethodFn;
+  get: MethodFn;
+  getConfig: () => Config;
+  head: MethodFn;
+  options: MethodFn;
+  patch: MethodFn;
+  post: MethodFn;
+  put: MethodFn;
+  request: RequestFn;
+  setConfig: (config: Config) => Config;
+  trace: MethodFn;
+}
+
+export interface Config {
+  /**
+   * Auth token or a function returning auth token. The resolved value will be
+   * added to the request payload as defined by its `security` array.
+   */
+  auth?: ((auth: Auth) => Promise<AuthToken> | AuthToken) | AuthToken;
+  /**
+   * A function for serializing request body parameter. By default,
+   * {@link JSON.stringify()} will be used.
+   */
+  bodySerializer?: BodySerializer | null;
+  /**
+   * An object containing any HTTP headers that you want to pre-populate your
+   * `Headers` object with.
+   *
+   * {@link https://developer.mozilla.org/docs/Web/API/Headers/Headers#init See more}
+   */
+  headers?:
+    | RequestInit['headers']
+    | Record<
+        string,
+        | string
+        | number
+        | boolean
+        | (string | number | boolean)[]
+        | null
+        | undefined
+        | unknown
+      >;
+  /**
+   * The request method.
+   *
+   * {@link https://developer.mozilla.org/docs/Web/API/fetch#method See more}
+   */
+  method?:
+    | 'CONNECT'
+    | 'DELETE'
+    | 'GET'
+    | 'HEAD'
+    | 'OPTIONS'
+    | 'PATCH'
+    | 'POST'
+    | 'PUT'
+    | 'TRACE';
+  /**
+   * A function for serializing request query parameters. By default, arrays
+   * will be exploded in form style, objects will be exploded in deepObject
+   * style, and reserved characters are percent-encoded.
+   *
+   * This method will have no effect if the native `paramsSerializer()` Axios
+   * API function is used.
+   *
+   * {@link https://swagger.io/docs/specification/serialization/#query View examples}
+   */
+  querySerializer?: QuerySerializer | QuerySerializerOptions;
+  /**
+   * A function transforming response data before it's returned. This is useful
+   * for post-processing data, e.g. converting ISO strings into Date objects.
+   */
+  responseTransformer?: (data: unknown) => Promise<unknown>;
+  /**
+   * A function validating response data. This is useful if you want to ensure
+   * the response conforms to the desired shape, so it can be safely passed to
+   * the transformers and returned to the user.
+   */
+  responseValidator?: (data: unknown) => Promise<unknown>;
+}

examples/openapi-ts-sample/src/client/sdk.gen.ts

···
 // This file is auto-generated by @hey-api/openapi-ts
 
-import type {
-  Client,
-  Options as ClientOptions,
-  TDataShape,
-} from '@hey-api/client-fetch';
-
+import type { Client, Options as ClientOptions, TDataShape } from './client';
 import { client as _heyApiClient } from './client.gen';
 import type {
   AddPetData,
···
     ...options,
     headers: {
       'Content-Type': 'application/json',
-      ...options?.headers,
+      ...options.headers,
     },
   });
 
···
     ...options,
     headers: {
       'Content-Type': 'application/json',
-      ...options?.headers,
+      ...options.headers,
     },
   });
 
···
     ...options,
     headers: {
       'Content-Type': 'application/octet-stream',
-      ...options?.headers,
+      ...options.headers,
     },
   });
 
···
     ...options,
     headers: {
       'Content-Type': 'application/json',
-      ...options?.headers,
+      ...options.headers,
     },
   });

examples/openapi-ts-sample/src/hey-api.ts

···
-import type { CreateClientConfig } from '@hey-api/client-fetch';
+import type { CreateClientConfig } from './client/client';
 
 export const createClientConfig: CreateClientConfig = (config) => ({
   ...config,

examples/openapi-ts-tanstack-angular-query-experimental/package.json

···
     "@angular/platform-browser": "^19.2.0",
     "@angular/platform-browser-dynamic": "^19.2.0",
     "@angular/router": "^19.2.0",
-    "@hey-api/client-fetch": "workspace:*",
     "@tanstack/angular-query-experimental": "5.73.3",
     "rxjs": "~7.8.0",
     "tslib": "^2.8.1",

examples/openapi-ts-tanstack-angular-query-experimental/src/client/client.gen.ts

···
   type Config,
   createClient,
   createConfig,
-} from '@hey-api/client-fetch';
-
+} from './client';
 import type { ClientOptions } from './types.gen';
 
 /**

examples/openapi-ts-tanstack-angular-query-experimental/src/client/client/client.ts

···
+import type { Client, Config, RequestOptions } from './types';
+import {
+  buildUrl,
+  createConfig,
+  createInterceptors,
+  getParseAs,
+  mergeConfigs,
+  mergeHeaders,
+  setAuthParams,
+} from './utils';
+
+type ReqInit = Omit<RequestInit, 'body' | 'headers'> & {
+  body?: any;
+  headers: ReturnType<typeof mergeHeaders>;
+};
+
+export const createClient = (config: Config = {}): Client => {
+  let _config = mergeConfigs(createConfig(), config);
+
+  const getConfig = (): Config => ({ ..._config });
+
+  const setConfig = (config: Config): Config => {
+    _config = mergeConfigs(_config, config);
+    return getConfig();
+  };
+
+  const interceptors = createInterceptors<
+    Request,
+    Response,
+    unknown,
+    RequestOptions
+  >();
+
+  const request: Client['request'] = async (options) => {
+    const opts = {
+      ..._config,
+      ...options,
+      fetch: options.fetch ?? _config.fetch ?? globalThis.fetch,
+      headers: mergeHeaders(_config.headers, options.headers),
+    };
+
+    if (opts.security) {
+      await setAuthParams({
+        ...opts,
+        security: opts.security,
+      });
+    }
+
+    if (opts.body && opts.bodySerializer) {
+      opts.body = opts.bodySerializer(opts.body);
+    }
+
+    // remove Content-Type header if body is empty to avoid sending invalid requests
+    if (opts.body === undefined || opts.body === '') {
+      opts.headers.delete('Content-Type');
+    }
+
+    const url = buildUrl(opts);
+    const requestInit: ReqInit = {
+      redirect: 'follow',
+      ...opts,
+    };
+
+    let request = new Request(url, requestInit);
+
+    for (const fn of interceptors.request._fns) {
+      if (fn) {
+        request = await fn(request, opts);
+      }
+    }
+
+    // fetch must be assigned here, otherwise it would throw the error:
+    // TypeError: Failed to execute 'fetch' on 'Window': Illegal invocation
+    const _fetch = opts.fetch!;
+    let response = await _fetch(request);
+
+    for (const fn of interceptors.response._fns) {
+      if (fn) {
+        response = await fn(response, request, opts);
+      }
+    }
+
+    const result = {
+      request,
+      response,
+    };
+
+    if (response.ok) {
+      if (
+        response.status === 204 ||
+        response.headers.get('Content-Length') === '0'
+      ) {
+        return opts.responseStyle === 'data'
+          ? {}
+          : {
+              data: {},
+              ...result,
+            };
+      }
+
+      const parseAs =
+        (opts.parseAs === 'auto'
+          ? getParseAs(response.headers.get('Content-Type'))
+          : opts.parseAs) ?? 'json';
+
+      if (parseAs === 'stream') {
+        return opts.responseStyle === 'data'
+          ? response.body
+          : {
+              data: response.body,
+              ...result,
+            };
+      }
+
+      let data = await response[parseAs]();
+      if (parseAs === 'json') {
+        if (opts.responseValidator) {
+          await opts.responseValidator(data);
+        }
+
+        if (opts.responseTransformer) {
+          data = await opts.responseTransformer(data);
+        }
+      }
+
+      return opts.responseStyle === 'data'
+        ? data
+        : {
+            data,
+            ...result,
+          };
+    }
+
+    let error = await response.text();
+
+    try {
+      error = JSON.parse(error);
+    } catch {
+      // noop
+    }
+
+    let finalError = error;
+
+    for (const fn of interceptors.error._fns) {
+      if (fn) {
+        finalError = (await fn(error, response, request, opts)) as string;
+      }
+    }
+
+    finalError = finalError || ({} as string);
+
+    if (opts.throwOnError) {
+      throw finalError;
+    }
+
+    // TODO: we probably want to return error and improve types
+    return opts.responseStyle === 'data'
+      ? undefined
+      : {
+          error: finalError,
+          ...result,
+        };
+  };
+
+  return {
+    buildUrl,
+    connect: (options) => request({ ...options, method: 'CONNECT' }),
+    delete: (options) => request({ ...options, method: 'DELETE' }),
+    get: (options) => request({ ...options, method: 'GET' }),
+    getConfig,
+    head: (options) => request({ ...options, method: 'HEAD' }),
+    interceptors,
+    options: (options) => request({ ...options, method: 'OPTIONS' }),
+    patch: (options) => request({ ...options, method: 'PATCH' }),
+    post: (options) => request({ ...options, method: 'POST' }),
+    put: (options) => request({ ...options, method: 'PUT' }),
+    request,
+    setConfig,
+    trace: (options) => request({ ...options, method: 'TRACE' }),
+  };
+};

examples/openapi-ts-tanstack-angular-query-experimental/src/client/client/index.ts

···
+export type { Auth } from '../core/auth';
+export type { QuerySerializerOptions } from '../core/bodySerializer';
+export {
+  formDataBodySerializer,
+  jsonBodySerializer,
+  urlSearchParamsBodySerializer,
+} from '../core/bodySerializer';
+export { buildClientParams } from '../core/params';
+export { createClient } from './client';
+export type {
+  Client,
+  ClientOptions,
+  Config,
+  CreateClientConfig,
+  Options,
+  OptionsLegacyParser,
+  RequestOptions,
+  RequestResult,
+  ResponseStyle,
+  TDataShape,
+} from './types';
+export { createConfig, mergeHeaders } from './utils';

examples/openapi-ts-tanstack-angular-query-experimental/src/client/client/types.ts

···
+import type { Auth } from '../core/auth';
+import type { Client as CoreClient, Config as CoreConfig } from '../core/types';
+import type { Middleware } from './utils';
+
+export type ResponseStyle = 'data' | 'fields';
+
+export interface Config<T extends ClientOptions = ClientOptions>
+  extends Omit<RequestInit, 'body' | 'headers' | 'method'>,
+    CoreConfig {
+  /**
+   * Base URL for all requests made by this client.
+   */
+  baseUrl?: T['baseUrl'];
+  /**
+   * Fetch API implementation. You can use this option to provide a custom
+   * fetch instance.
+   *
+   * @default globalThis.fetch
+   */
+  fetch?: (request: Request) => ReturnType<typeof fetch>;
+  /**
+   * Please don't use the Fetch client for Next.js applications. The `next`
+   * options won't have any effect.
+   *
+   * Install {@link https://www.npmjs.com/package/@hey-api/client-next `@hey-api/client-next`} instead.
+   */
+  next?: never;
+  /**
+   * Return the response data parsed in a specified format. By default, `auto`
+   * will infer the appropriate method from the `Content-Type` response header.
+   * You can override this behavior with any of the {@link Body} methods.
+   * Select `stream` if you don't want to parse response data at all.
+   *
+   * @default 'auto'
+   */
+  parseAs?: Exclude<keyof Body, 'body' | 'bodyUsed'> | 'auto' | 'stream';
+  /**
+   * Should we return only data or multiple fields (data, error, response, etc.)?
+   *
+   * @default 'fields'
+   */
+  responseStyle?: ResponseStyle;
+  /**
+   * Throw an error instead of returning it in the response?
+   *
+   * @default false
+   */
+  throwOnError?: T['throwOnError'];
+}
+
+export interface RequestOptions<
+  TResponseStyle extends ResponseStyle = 'fields',
+  ThrowOnError extends boolean = boolean,
+  Url extends string = string,
+> extends Config<{
+    responseStyle: TResponseStyle;
+    throwOnError: ThrowOnError;
+  }> {
+  /**
+   * Any body that you want to add to your request.
+   *
+   * {@link https://developer.mozilla.org/docs/Web/API/fetch#body}
+   */
+  body?: unknown;
+  path?: Record<string, unknown>;
+  query?: Record<string, unknown>;
+  /**
+   * Security mechanism(s) to use for the request.
+   */
+  security?: ReadonlyArray<Auth>;
+  url: Url;
+}
+
+export type RequestResult<
+  TData = unknown,
+  TError = unknown,
+  ThrowOnError extends boolean = boolean,
+  TResponseStyle extends ResponseStyle = 'fields',
+> = ThrowOnError extends true
+  ? Promise<
+      TResponseStyle extends 'data'
+        ? TData extends Record<string, unknown>
+          ? TData[keyof TData]
+          : TData
+        : {
+            data: TData extends Record<string, unknown>
+              ? TData[keyof TData]
+              : TData;
+            request: Request;
+            response: Response;
+          }
+    >
+  : Promise<
+      TResponseStyle extends 'data'
+        ?
+            | (TData extends Record<string, unknown>
+                ? TData[keyof TData]
+                : TData)
+            | undefined
+        : (
+            | {
+                data: TData extends Record<string, unknown>
+                  ? TData[keyof TData]
+                  : TData;
+                error: undefined;
+              }
+            | {
+                data: undefined;
+                error: TError extends Record<string, unknown>
+                  ? TError[keyof TError]
+                  : TError;
+              }
+          ) & {
+            request: Request;
+            response: Response;
+          }
+    >;
+
+export interface ClientOptions {
+  baseUrl?: string;
+  responseStyle?: ResponseStyle;
+  throwOnError?: boolean;
+}
+
+type MethodFn = <
+  TData = unknown,
+  TError = unknown,
+  ThrowOnError extends boolean = false,
+  TResponseStyle extends ResponseStyle = 'fields',
+>(
+  options: Omit<RequestOptions<TResponseStyle, ThrowOnError>, 'method'>,
+) => RequestResult<TData, TError, ThrowOnError, TResponseStyle>;
+
+type RequestFn = <
+  TData = unknown,
+  TError = unknown,
+  ThrowOnError extends boolean = false,
+  TResponseStyle extends ResponseStyle = 'fields',
+>(
+  options: Omit<RequestOptions<TResponseStyle, ThrowOnError>, 'method'> &
+    Pick<Required<RequestOptions<TResponseStyle, ThrowOnError>>, 'method'>,
+) => RequestResult<TData, TError, ThrowOnError, TResponseStyle>;
+
+type BuildUrlFn = <
+  TData extends {
+    body?: unknown;
+    path?: Record<string, unknown>;
+    query?: Record<string, unknown>;
+    url: string;
+  },
+>(
+  options: Pick<TData, 'url'> & Options<TData>,
+) => string;
+
+export type Client = CoreClient<RequestFn, Config, MethodFn, BuildUrlFn> & {
+  interceptors: Middleware<Request, Response, unknown, RequestOptions>;
+};
+
+/**
+ * The `createClientConfig()` function will be called on client initialization
+ * and the returned object will become the client's initial configuration.
+ *
+ * You may want to initialize your client this way instead of calling
+ * `setConfig()`. This is useful for example if you're using Next.js
+ * to ensure your client always has the correct values.
+ */
+export type CreateClientConfig<T extends ClientOptions = ClientOptions> = (
+  override?: Config<ClientOptions & T>,
+) => Config<Required<ClientOptions> & T>;
+
+export interface TDataShape {
+  body?: unknown;
+  headers?: unknown;
+  path?: unknown;
+  query?: unknown;
+  url: string;
+}
+
+type OmitKeys<T, K> = Pick<T, Exclude<keyof T, K>>;
+
+export type Options<
+  TData extends TDataShape = TDataShape,
+  ThrowOnError extends boolean = boolean,
+  TResponseStyle extends ResponseStyle = 'fields',
+> = OmitKeys<
+  RequestOptions<TResponseStyle, ThrowOnError>,
+  'body' | 'path' | 'query' | 'url'
+> &
+  Omit<TData, 'url'>;
+
+export type OptionsLegacyParser<
+  TData = unknown,
+  ThrowOnError extends boolean = boolean,
+  TResponseStyle extends ResponseStyle = 'fields',
+> = TData extends { body?: any }
+  ? TData extends { headers?: any }
+    ? OmitKeys<
+        RequestOptions<TResponseStyle, ThrowOnError>,
+        'body' | 'headers' | 'url'
+      > &
+        TData
+    : OmitKeys<RequestOptions<TResponseStyle, ThrowOnError>, 'body' | 'url'> &
+        TData &
+        Pick<RequestOptions<TResponseStyle, ThrowOnError>, 'headers'>
+  : TData extends { headers?: any }
+    ? OmitKeys<
+        RequestOptions<TResponseStyle, ThrowOnError>,
+        'headers' | 'url'
+      > &
+        TData &
+        Pick<RequestOptions<TResponseStyle, ThrowOnError>, 'body'>
+    : OmitKeys<RequestOptions<TResponseStyle, ThrowOnError>, 'url'> & TData;

examples/openapi-ts-tanstack-angular-query-experimental/src/client/client/utils.ts

···
+import { getAuthToken } from '../core/auth';
+import type {
+  QuerySerializer,
+  QuerySerializerOptions,
+} from '../core/bodySerializer';
+import { jsonBodySerializer } from '../core/bodySerializer';
+import {
+  serializeArrayParam,
+  serializeObjectParam,
+  serializePrimitiveParam,
+} from '../core/pathSerializer';
+import type { Client, ClientOptions, Config, RequestOptions } from './types';
+
+interface PathSerializer {
+  path: Record<string, unknown>;
+  url: string;
+}
+
+const PATH_PARAM_RE = /\{[^{}]+\}/g;
+
+type ArrayStyle = 'form' | 'spaceDelimited' | 'pipeDelimited';
+type MatrixStyle = 'label' | 'matrix' | 'simple';
+type ArraySeparatorStyle = ArrayStyle | MatrixStyle;
+
+const defaultPathSerializer = ({ path, url: _url }: PathSerializer) => {
+  let url = _url;
+  const matches = _url.match(PATH_PARAM_RE);
+  if (matches) {
+    for (const match of matches) {
+      let explode = false;
+      let name = match.substring(1, match.length - 1);
+      let style: ArraySeparatorStyle = 'simple';
+
+      if (name.endsWith('*')) {
+        explode = true;
+        name = name.substring(0, name.length - 1);
+      }
+
+      if (name.startsWith('.')) {
+        name = name.substring(1);
+        style = 'label';
+      } else if (name.startsWith(';')) {
+        name = name.substring(1);
+        style = 'matrix';
+      }
+
+      const value = path[name];
+
+      if (value === undefined || value === null) {
+        continue;
+      }
+
+      if (Array.isArray(value)) {
+        url = url.replace(
+          match,
+          serializeArrayParam({ explode, name, style, value }),
+        );
+        continue;
+      }
+
+      if (typeof value === 'object') {
+        url = url.replace(
+          match,
+          serializeObjectParam({
+            explode,
+            name,
+            style,
+            value: value as Record<string, unknown>,
+            valueOnly: true,
+          }),
+        );
+        continue;
+      }
+
+      if (style === 'matrix') {
+        url = url.replace(
+          match,
+          `;${serializePrimitiveParam({
+            name,
+            value: value as string,
+          })}`,
+        );
+        continue;
+      }
+
+      const replaceValue = encodeURIComponent(
+        style === 'label' ? `.${value as string}` : (value as string),
+      );
+      url = url.replace(match, replaceValue);
+    }
+  }
+  return url;
+};
+
+export const createQuerySerializer = <T = unknown>({
+  allowReserved,
+  array,
+  object,
+}: QuerySerializerOptions = {}) => {
+  const querySerializer = (queryParams: T) => {
+    const search: string[] = [];
+    if (queryParams && typeof queryParams === 'object') {
+      for (const name in queryParams) {
+        const value = queryParams[name];
+
+        if (value === undefined || value === null) {
+          continue;
+        }
+
+        if (Array.isArray(value)) {
+          const serializedArray = serializeArrayParam({
+            allowReserved,
+            explode: true,
+            name,
+            style: 'form',
+            value,
+            ...array,
+          });
+          if (serializedArray) search.push(serializedArray);
+        } else if (typeof value === 'object') {
+          const serializedObject = serializeObjectParam({
+            allowReserved,
+            explode: true,
+            name,
+            style: 'deepObject',
+            value: value as Record<string, unknown>,
+            ...object,
+          });
+          if (serializedObject) search.push(serializedObject);
+        } else {
+          const serializedPrimitive = serializePrimitiveParam({
+            allowReserved,
+            name,
+            value: value as string,
+          });
+          if (serializedPrimitive) search.push(serializedPrimitive);
+        }
+      }
+    }
+    return search.join('&');
+  };
+  return querySerializer;
+};
+
+/**
+ * Infers parseAs value from provided Content-Type header.
+ */
+export const getParseAs = (
+  contentType: string | null,
+): Exclude<Config['parseAs'], 'auto'> => {
+  if (!contentType) {
+    // If no Content-Type header is provided, the best we can do is return the raw response body,
+    // which is effectively the same as the 'stream' option.
+    return 'stream';
+  }
+
+  const cleanContent = contentType.split(';')[0]?.trim();
+
+  if (!cleanContent) {
+    return;
+  }
+
+  if (
+    cleanContent.startsWith('application/json') ||
+    cleanContent.endsWith('+json')
+  ) {
+    return 'json';
+  }
+
+  if (cleanContent === 'multipart/form-data') {
+    return 'formData';
+  }
+
+  if (
+    ['application/', 'audio/', 'image/', 'video/'].some((type) =>
+      cleanContent.startsWith(type),
+    )
+  ) {
+    return 'blob';
+  }
+
+  if (cleanContent.startsWith('text/')) {
+    return 'text';
+  }
+};
+
+export const setAuthParams = async ({
+  security,
+  ...options
+}: Pick<Required<RequestOptions>, 'security'> &
+  Pick<RequestOptions, 'auth' | 'query'> & {
+    headers: Headers;
+  }) => {
+  for (const auth of security) {
+    const token = await getAuthToken(auth, options.auth);
+
+    if (!token) {
+      continue;
+    }
+
+    const name = auth.name ?? 'Authorization';
+
+    switch (auth.in) {
+      case 'query':
+        if (!options.query) {
+          options.query = {};
+        }
+        options.query[name] = token;
+        break;
+      case 'cookie':
+        options.headers.append('Cookie', `${name}=${token}`);
+        break;
+      case 'header':
+      default:
+        options.headers.set(name, token);
+        break;
+    }
+
+    return;
+  }
+};
+
+export const buildUrl: Client['buildUrl'] = (options) => {
+  const url = getUrl({
+    baseUrl: options.baseUrl as string,
+    path: options.path,
+    query: options.query,
+    querySerializer:
+      typeof options.querySerializer === 'function'
+        ? options.querySerializer
+        : createQuerySerializer(options.querySerializer),
+    url: options.url,
+  });
+  return url;
+};
+
+export const getUrl = ({
+  baseUrl,
+  path,
+  query,
+  querySerializer,
+  url: _url,
+}: {
+  baseUrl?: string;
+  path?: Record<string, unknown>;
+  query?: Record<string, unknown>;
+  querySerializer: QuerySerializer;
+  url: string;
+}) => {
+  const pathUrl = _url.startsWith('/') ? _url : `/${_url}`;
+  let url = (baseUrl ?? '') + pathUrl;
+  if (path) {
+    url = defaultPathSerializer({ path, url });
+  }
+  let search = query ? querySerializer(query) : '';
+  if (search.startsWith('?')) {
+    search = search.substring(1);
+  }
+  if (search) {
+    url += `?${search}`;
+  }
+  return url;
+};
+
+export const mergeConfigs = (a: Config, b: Config): Config => {
+  const config = { ...a, ...b };
+  if (config.baseUrl?.endsWith('/')) {
+    config.baseUrl = config.baseUrl.substring(0, config.baseUrl.length - 1);
+  }
+  config.headers = mergeHeaders(a.headers, b.headers);
+  return config;
+};
+
+export const mergeHeaders = (
+  ...headers: Array<Required<Config>['headers'] | undefined>
+): Headers => {
+  const mergedHeaders = new Headers();
+  for (const header of headers) {
+    if (!header || typeof header !== 'object') {
+      continue;
+    }
+
+    const iterator =
+      header instanceof Headers ? header.entries() : Object.entries(header);
+
+    for (const [key, value] of iterator) {
+      if (value === null) {
+        mergedHeaders.delete(key);
+      } else if (Array.isArray(value)) {
+        for (const v of value) {
+          mergedHeaders.append(key, v as string);
+        }
+      } else if (value !== undefined) {
+        // assume object headers are meant to be JSON stringified, i.e. their
+        // content value in OpenAPI specification is 'application/json'
+        mergedHeaders.set(
+          key,
+          typeof value === 'object' ? JSON.stringify(value) : (value as string),
+        );
+      }
+    }
+  }
+  return mergedHeaders;
+};
+
+type ErrInterceptor<Err, Res, Req, Options> = (
+  error: Err,
+  response: Res,
+  request: Req,
+  options: Options,
+) => Err | Promise<Err>;
+
+type ReqInterceptor<Req, Options> = (
+  request: Req,
+  options: Options,
+) => Req | Promise<Req>;
+
+type ResInterceptor<Res, Req, Options> = (
+  response: Res,
+  request: Req,
+  options: Options,
+) => Res | Promise<Res>;
+
+class Interceptors<Interceptor> {
+  _fns: (Interceptor | null)[];
+
+  constructor() {
+    this._fns = [];
+  }
+
+  clear() {
+    this._fns = [];
+  }
+
+  getInterceptorIndex(id: number | Interceptor): number {
+    if (typeof id === 'number') {
+      return this._fns[id] ? id : -1;
+    } else {
+      return this._fns.indexOf(id);
+    }
+  }
+  exists(id: number | Interceptor) {
+    const index = this.getInterceptorIndex(id);
+    return !!this._fns[index];
+  }
+
+  eject(id: number | Interceptor) {
+    const index = this.getInterceptorIndex(id);
+    if (this._fns[index]) {
+      this._fns[index] = null;
+    }
+  }
+
+  update(id: number | Interceptor, fn: Interceptor) {
+    const index = this.getInterceptorIndex(id);
+    if (this._fns[index]) {
+      this._fns[index] = fn;
+      return id;
+    } else {
+      return false;
+    }
+  }
+
+  use(fn: Interceptor) {
+    this._fns = [...this._fns, fn];
+    return this._fns.length - 1;
+  }
+}
+
+// `createInterceptors()` response, meant for external use as it does not
+// expose internals
+export interface Middleware<Req, Res, Err, Options> {
+  error: Pick<
+    Interceptors<ErrInterceptor<Err, Res, Req, Options>>,
+    'eject' | 'use'
+  >;
+  request: Pick<Interceptors<ReqInterceptor<Req, Options>>, 'eject' | 'use'>;
+  response: Pick<
+    Interceptors<ResInterceptor<Res, Req, Options>>,
+    'eject' | 'use'
+  >;
+}
+
+// do not add `Middleware` as return type so we can use _fns internally
+export const createInterceptors = <Req, Res, Err, Options>() => ({
+  error: new Interceptors<ErrInterceptor<Err, Res, Req, Options>>(),
+  request: new Interceptors<ReqInterceptor<Req, Options>>(),
+  response: new Interceptors<ResInterceptor<Res, Req, Options>>(),
+});
+
+const defaultQuerySerializer = createQuerySerializer({
+  allowReserved: false,
+  array: {
+    explode: true,
+    style: 'form',
+  },
+  object: {
+    explode: true,
+    style: 'deepObject',
+  },
+});
+
+const defaultHeaders = {
+  'Content-Type': 'application/json',
+};
+
+export const createConfig = <T extends ClientOptions = ClientOptions>(
+  override: Config<Omit<ClientOptions, keyof T> & T> = {},
+): Config<Omit<ClientOptions, keyof T> & T> => ({
+  ...jsonBodySerializer,
+  headers: defaultHeaders,
+  parseAs: 'auto',
+  querySerializer: defaultQuerySerializer,
+  ...override,
+});

examples/openapi-ts-tanstack-angular-query-experimental/src/client/core/auth.ts

···
+export type AuthToken = string | undefined;
+
+export interface Auth {
+  /**
+   * Which part of the request do we use to send the auth?
+   *
+   * @default 'header'
+   */
+  in?: 'header' | 'query' | 'cookie';
+  /**
+   * Header or query parameter name.
+   *
+   * @default 'Authorization'
+   */
+  name?: string;
+  scheme?: 'basic' | 'bearer';
+  type: 'apiKey' | 'http';
+}
+
+export const getAuthToken = async (
+  auth: Auth,
+  callback: ((auth: Auth) => Promise<AuthToken> | AuthToken) | AuthToken,
+): Promise<string | undefined> => {
+  const token =
+    typeof callback === 'function' ? await callback(auth) : callback;
+
+  if (!token) {
+    return;
+  }
+
+  if (auth.scheme === 'bearer') {
+    return `Bearer ${token}`;
+  }
+
+  if (auth.scheme === 'basic') {
+    return `Basic ${btoa(token)}`;
+  }
+
+  return token;
+};

examples/openapi-ts-tanstack-angular-query-experimental/src/client/core/bodySerializer.ts

···
+import type {
+  ArrayStyle,
+  ObjectStyle,
+  SerializerOptions,
+} from './pathSerializer';
+
+export type QuerySerializer = (query: Record<string, unknown>) => string;
+
+export type BodySerializer = (body: any) => any;
+
+export interface QuerySerializerOptions {
+  allowReserved?: boolean;
+  array?: SerializerOptions<ArrayStyle>;
+  object?: SerializerOptions<ObjectStyle>;
+}
+
+const serializeFormDataPair = (data: FormData, key: string, value: unknown) => {
+  if (typeof value === 'string' || value instanceof Blob) {
+    data.append(key, value);
+  } else {
+    data.append(key, JSON.stringify(value));
+  }
+};
+
+const serializeUrlSearchParamsPair = (
+  data: URLSearchParams,
+  key: string,
+  value: unknown,
+) => {
+  if (typeof value === 'string') {
+    data.append(key, value);
+  } else {
+    data.append(key, JSON.stringify(value));
+  }
+};
+
+export const formDataBodySerializer = {
+  bodySerializer: <T extends Record<string, any> | Array<Record<string, any>>>(
+    body: T,
+  ) => {
+    const data = new FormData();
+
+    Object.entries(body).forEach(([key, value]) => {
+      if (value === undefined || value === null) {
+        return;
+      }
+      if (Array.isArray(value)) {
+        value.forEach((v) => serializeFormDataPair(data, key, v));
+      } else {
+        serializeFormDataPair(data, key, value);
+      }
+    });
+
+    return data;
+  },
+};
+
+export const jsonBodySerializer = {
+  bodySerializer: <T>(body: T) =>
+    JSON.stringify(body, (key, value) =>
+      typeof value === 'bigint' ? value.toString() : value,
+    ),
+};
+
+export const urlSearchParamsBodySerializer = {
+  bodySerializer: <T extends Record<string, any> | Array<Record<string, any>>>(
+    body: T,
+  ) => {
+    const data = new URLSearchParams();
+
+    Object.entries(body).forEach(([key, value]) => {
+      if (value === undefined || value === null) {
+        return;
+      }
+      if (Array.isArray(value)) {
+        value.forEach((v) => serializeUrlSearchParamsPair(data, key, v));
+      } else {
+        serializeUrlSearchParamsPair(data, key, value);
+      }
+    });
+
+    return data.toString();
+  },
+};

examples/openapi-ts-tanstack-angular-query-experimental/src/client/core/params.ts

···
+type Slot = 'body' | 'headers' | 'path' | 'query';
+
+export type Field =
+  | {
+      in: Exclude<Slot, 'body'>;
+      key: string;
+      map?: string;
+    }
+  | {
+      in: Extract<Slot, 'body'>;
+      key?: string;
+      map?: string;
+    };
+
+export interface Fields {
+  allowExtra?: Partial<Record<Slot, boolean>>;
+  args?: ReadonlyArray<Field>;
+}
+
+export type FieldsConfig = ReadonlyArray<Field | Fields>;
+
+const extraPrefixesMap: Record<string, Slot> = {
+  $body_: 'body',
+  $headers_: 'headers',
+  $path_: 'path',
+  $query_: 'query',
+};
+const extraPrefixes = Object.entries(extraPrefixesMap);
+
+type KeyMap = Map<
+  string,
+  {
+    in: Slot;
+    map?: string;
+  }
+>;
+
+const buildKeyMap = (fields: FieldsConfig, map?: KeyMap): KeyMap => {
+  if (!map) {
+    map = new Map();
+  }
+
+  for (const config of fields) {
+    if ('in' in config) {
+      if (config.key) {
+        map.set(config.key, {
+          in: config.in,
+          map: config.map,
+        });
+      }
+    } else if (config.args) {
+      buildKeyMap(config.args, map);
+    }
+  }
+
+  return map;
+};
+
+interface Params {
+  body: unknown;
+  headers: Record<string, unknown>;
+  path: Record<string, unknown>;
+  query: Record<string, unknown>;
+}
+
+const stripEmptySlots = (params: Params) => {
+  for (const [slot, value] of Object.entries(params)) {
+    if (value && typeof value === 'object' && !Object.keys(value).length) {
+      delete params[slot as Slot];
+    }
+  }
+};
+
+export const buildClientParams = (
+  args: ReadonlyArray<unknown>,
+  fields: FieldsConfig,
+) => {
+  const params: Params = {
+    body: {},
+    headers: {},
+    path: {},
+    query: {},
+  };
+
+  const map = buildKeyMap(fields);
+
+  let config: FieldsConfig[number] | undefined;
+
+  for (const [index, arg] of args.entries()) {
+    if (fields[index]) {
+      config = fields[index];
+    }
+
+    if (!config) {
+      continue;
+    }
+
+    if ('in' in config) {
+      if (config.key) {
+        const field = map.get(config.key)!;
+        const name = field.map || config.key;
+        (params[field.in] as Record<string, unknown>)[name] = arg;
+      } else {
+        params.body = arg;
+      }
+    } else {
+      for (const [key, value] of Object.entries(arg ?? {})) {
+        const field = map.get(key);
+
+        if (field) {
+          const name = field.map || key;
+          (params[field.in] as Record<string, unknown>)[name] = value;
+        } else {
+          const extra = extraPrefixes.find(([prefix]) =>
+            key.startsWith(prefix),
+          );
+
+          if (extra) {
+            const [prefix, slot] = extra;
+            (params[slot] as Record<string, unknown>)[
+              key.slice(prefix.length)
+            ] = value;
+          } else {
+            for (const [slot, allowed] of Object.entries(
+              config.allowExtra ?? {},
+            )) {
+              if (allowed) {
+                (params[slot as Slot] as Record<string, unknown>)[key] = value;
+                break;
+              }
+            }
+          }
+        }
+      }
+    }
+  }
+
+  stripEmptySlots(params);
+
+  return params;
+};

examples/openapi-ts-tanstack-angular-query-experimental/src/client/core/pathSerializer.ts

···
+interface SerializeOptions<T>
+  extends SerializePrimitiveOptions,
+    SerializerOptions<T> {}
+
+interface SerializePrimitiveOptions {
+  allowReserved?: boolean;
+  name: string;
+}
+
+export interface SerializerOptions<T> {
+  /**
+   * @default true
+   */
+  explode: boolean;
+  style: T;
+}
+
+export type ArrayStyle = 'form' | 'spaceDelimited' | 'pipeDelimited';
+export type ArraySeparatorStyle = ArrayStyle | MatrixStyle;
+type MatrixStyle = 'label' | 'matrix' | 'simple';
+export type ObjectStyle = 'form' | 'deepObject';
+type ObjectSeparatorStyle = ObjectStyle | MatrixStyle;
+
+interface SerializePrimitiveParam extends SerializePrimitiveOptions {
+  value: string;
+}
+
+export const separatorArrayExplode = (style: ArraySeparatorStyle) => {
+  switch (style) {
+    case 'label':
+      return '.';
+    case 'matrix':
+      return ';';
+    case 'simple':
+      return ',';
+    default:
+      return '&';
+  }
+};
+
+export const separatorArrayNoExplode = (style: ArraySeparatorStyle) => {
+  switch (style) {
+    case 'form':
+      return ',';
+    case 'pipeDelimited':
+      return '|';
+    case 'spaceDelimited':
+      return '%20';
+    default:
+      return ',';
+  }
+};
+
+export const separatorObjectExplode = (style: ObjectSeparatorStyle) => {
+  switch (style) {
+    case 'label':
+      return '.';
+    case 'matrix':
+      return ';';
+    case 'simple':
+      return ',';
+    default:
+      return '&';
+  }
+};
+
+export const serializeArrayParam = ({
+  allowReserved,
+  explode,
+  name,
+  style,
+  value,
+}: SerializeOptions<ArraySeparatorStyle> & {
+  value: unknown[];
+}) => {
+  if (!explode) {
+    const joinedValues = (
+      allowReserved ? value : value.map((v) => encodeURIComponent(v as string))
+    ).join(separatorArrayNoExplode(style));
+    switch (style) {
+      case 'label':
+        return `.${joinedValues}`;
+      case 'matrix':
+        return `;${name}=${joinedValues}`;
+      case 'simple':
+        return joinedValues;
+      default:
+        return `${name}=${joinedValues}`;
+    }
+  }
+
+  const separator = separatorArrayExplode(style);
+  const joinedValues = value
+    .map((v) => {
+      if (style === 'label' || style === 'simple') {
+        return allowReserved ? v : encodeURIComponent(v as string);
+      }
+
+      return serializePrimitiveParam({
+        allowReserved,
+        name,
+        value: v as string,
+      });
+    })
+    .join(separator);
+  return style === 'label' || style === 'matrix'
+    ? separator + joinedValues
+    : joinedValues;
+};
+
+export const serializePrimitiveParam = ({
+  allowReserved,
+  name,
+  value,
+}: SerializePrimitiveParam) => {
+  if (value === undefined || value === null) {
+    return '';
+  }
+
+  if (typeof value === 'object') {
+    throw new Error(
+      'Deeply-nested arrays/objects aren’t supported. Provide your own `querySerializer()` to handle these.',
+    );
+  }
+
+  return `${name}=${allowReserved ? value : encodeURIComponent(value)}`;
+};
+
+export const serializeObjectParam = ({
+  allowReserved,
+  explode,
+  name,
+  style,
+  value,
+  valueOnly,
+}: SerializeOptions<ObjectSeparatorStyle> & {
+  value: Record<string, unknown> | Date;
+  valueOnly?: boolean;
+}) => {
+  if (value instanceof Date) {
+    return valueOnly ? value.toISOString() : `${name}=${value.toISOString()}`;
+  }
+
+  if (style !== 'deepObject' && !explode) {
+    let values: string[] = [];
+    Object.entries(value).forEach(([key, v]) => {
+      values = [
+        ...values,
+        key,
+        allowReserved ? (v as string) : encodeURIComponent(v as string),
+      ];
+    });
+    const joinedValues = values.join(',');
+    switch (style) {
+      case 'form':
+        return `${name}=${joinedValues}`;
+      case 'label':
+        return `.${joinedValues}`;
+      case 'matrix':
+        return `;${name}=${joinedValues}`;
+      default:
+        return joinedValues;
+    }
+  }
+
+  const separator = separatorObjectExplode(style);
+  const joinedValues = Object.entries(value)
+    .map(([key, v]) =>
+      serializePrimitiveParam({
+        allowReserved,
+        name: style === 'deepObject' ? `${name}[${key}]` : key,
+        value: v as string,
+      }),
+    )
+    .join(separator);
+  return style === 'label' || style === 'matrix'
+    ? separator + joinedValues
+    : joinedValues;
+};

examples/openapi-ts-tanstack-angular-query-experimental/src/client/core/types.ts

···
+import type { Auth, AuthToken } from './auth';
+import type {
+  BodySerializer,
+  QuerySerializer,
+  QuerySerializerOptions,
+} from './bodySerializer';
+
+export interface Client<
+  RequestFn = never,
+  Config = unknown,
+  MethodFn = never,
+  BuildUrlFn = never,
+> {
+  /**
+   * Returns the final request URL.
+   */
+  buildUrl: BuildUrlFn;
+  connect: MethodFn;
+  delete: MethodFn;
+  get: MethodFn;
+  getConfig: () => Config;
+  head: MethodFn;
+  options: MethodFn;
+  patch: MethodFn;
+  post: MethodFn;
+  put: MethodFn;
+  request: RequestFn;
+  setConfig: (config: Config) => Config;
+  trace: MethodFn;
+}
+
+export interface Config {
+  /**
+   * Auth token or a function returning auth token. The resolved value will be
+   * added to the request payload as defined by its `security` array.
+   */
+  auth?: ((auth: Auth) => Promise<AuthToken> | AuthToken) | AuthToken;
+  /**
+   * A function for serializing request body parameter. By default,
+   * {@link JSON.stringify()} will be used.
+   */
+  bodySerializer?: BodySerializer | null;
+  /**
+   * An object containing any HTTP headers that you want to pre-populate your
+   * `Headers` object with.
+   *
+   * {@link https://developer.mozilla.org/docs/Web/API/Headers/Headers#init See more}
+   */
+  headers?:
+    | RequestInit['headers']
+    | Record<
+        string,
+        | string
+        | number
+        | boolean
+        | (string | number | boolean)[]
+        | null
+        | undefined
+        | unknown
+      >;
+  /**
+   * The request method.
+   *
+   * {@link https://developer.mozilla.org/docs/Web/API/fetch#method See more}
+   */
+  method?:
+    | 'CONNECT'
+    | 'DELETE'
+    | 'GET'
+    | 'HEAD'
+    | 'OPTIONS'
+    | 'PATCH'
+    | 'POST'
+    | 'PUT'
+    | 'TRACE';
+  /**
+   * A function for serializing request query parameters. By default, arrays
+   * will be exploded in form style, objects will be exploded in deepObject
+   * style, and reserved characters are percent-encoded.
+   *
+   * This method will have no effect if the native `paramsSerializer()` Axios
+   * API function is used.
+   *
+   * {@link https://swagger.io/docs/specification/serialization/#query View examples}
+   */
+  querySerializer?: QuerySerializer | QuerySerializerOptions;
+  /**
+   * A function transforming response data before it's returned. This is useful
+   * for post-processing data, e.g. converting ISO strings into Date objects.
+   */
+  responseTransformer?: (data: unknown) => Promise<unknown>;
+  /**
+   * A function validating response data. This is useful if you want to ensure
+   * the response conforms to the desired shape, so it can be safely passed to
+   * the transformers and returned to the user.
+   */
+  responseValidator?: (data: unknown) => Promise<unknown>;
+}

examples/openapi-ts-tanstack-angular-query-experimental/src/client/sdk.gen.ts

···
 // This file is auto-generated by @hey-api/openapi-ts
 
-import type {
-  Client,
-  Options as ClientOptions,
-  TDataShape,
-} from '@hey-api/client-fetch';
-
+import type { Client, Options as ClientOptions, TDataShape } from './client';
 import { client as _heyApiClient } from './client.gen';
 import type {
   AddPetData,
···
     ...options,
     headers: {
       'Content-Type': 'application/json',
-      ...options?.headers,
+      ...options.headers,
     },
   });
 
···
     ...options,
     headers: {
       'Content-Type': 'application/json',
-      ...options?.headers,
+      ...options.headers,
     },
   });
 
···
     ...options,
     headers: {
       'Content-Type': 'application/octet-stream',
-      ...options?.headers,
+      ...options.headers,
     },
   });
 
···
     ...options,
     headers: {
       'Content-Type': 'application/json',
-      ...options?.headers,
+      ...options.headers,
     },
   });

examples/openapi-ts-tanstack-react-query/package.json

···
     "typecheck": "tsc --noEmit"
   },
   "dependencies": {
-    "@hey-api/client-fetch": "workspace:*",
     "@radix-ui/react-form": "0.1.1",
     "@radix-ui/react-icons": "1.3.2",
     "@radix-ui/themes": "3.1.6",

examples/openapi-ts-tanstack-react-query/src/App.tsx

···
 import './App.css';
 
-import { createClient } from '@hey-api/client-fetch';
 import * as Form from '@radix-ui/react-form';
 import { DownloadIcon, PlusIcon, ReloadIcon } from '@radix-ui/react-icons';
 import {
···
   getPetByIdOptions,
   updatePetMutation,
 } from './client/@tanstack/react-query.gen';
+import { createClient } from './client/client';
 import { PetSchema } from './client/schemas.gen';
 import type { Pet } from './client/types.gen';
 

examples/openapi-ts-tanstack-react-query/src/client/client.gen.ts

···
   type Config,
   createClient,
   createConfig,
-} from '@hey-api/client-fetch';
-
+} from './client';
 import type { ClientOptions } from './types.gen';
 
 /**

examples/openapi-ts-tanstack-react-query/src/client/client/client.ts

···
+import type { Client, Config, RequestOptions } from './types';
+import {
+  buildUrl,
+  createConfig,
+  createInterceptors,
+  getParseAs,
+  mergeConfigs,
+  mergeHeaders,
+  setAuthParams,
+} from './utils';
+
+type ReqInit = Omit<RequestInit, 'body' | 'headers'> & {
+  body?: any;
+  headers: ReturnType<typeof mergeHeaders>;
+};
+
+export const createClient = (config: Config = {}): Client => {
+  let _config = mergeConfigs(createConfig(), config);
+
+  const getConfig = (): Config => ({ ..._config });
+
+  const setConfig = (config: Config): Config => {
+    _config = mergeConfigs(_config, config);
+    return getConfig();
+  };
+
+  const interceptors = createInterceptors<
+    Request,
+    Response,
+    unknown,
+    RequestOptions
+  >();
+
+  const request: Client['request'] = async (options) => {
+    const opts = {
+      ..._config,
+      ...options,
+      fetch: options.fetch ?? _config.fetch ?? globalThis.fetch,
+      headers: mergeHeaders(_config.headers, options.headers),
+    };
+
+    if (opts.security) {
+      await setAuthParams({
+        ...opts,
+        security: opts.security,
+      });
+    }
+
+    if (opts.body && opts.bodySerializer) {
+      opts.body = opts.bodySerializer(opts.body);
+    }
+
+    // remove Content-Type header if body is empty to avoid sending invalid requests
+    if (opts.body === undefined || opts.body === '') {
+      opts.headers.delete('Content-Type');
+    }
+
+    const url = buildUrl(opts);
+    const requestInit: ReqInit = {
+      redirect: 'follow',
+      ...opts,
+    };
+
+    let request = new Request(url, requestInit);
+
+    for (const fn of interceptors.request._fns) {
+      if (fn) {
+        request = await fn(request, opts);
+      }
+    }
+
+    // fetch must be assigned here, otherwise it would throw the error:
+    // TypeError: Failed to execute 'fetch' on 'Window': Illegal invocation
+    const _fetch = opts.fetch!;
+    let response = await _fetch(request);
+
+    for (const fn of interceptors.response._fns) {
+      if (fn) {
+        response = await fn(response, request, opts);
+      }
+    }
+
+    const result = {
+      request,
+      response,
+    };
+
+    if (response.ok) {
+      if (
+        response.status === 204 ||
+        response.headers.get('Content-Length') === '0'
+      ) {
+        return opts.responseStyle === 'data'
+          ? {}
+          : {
+              data: {},
+              ...result,
+            };
+      }
+
+      const parseAs =
+        (opts.parseAs === 'auto'
+          ? getParseAs(response.headers.get('Content-Type'))
+          : opts.parseAs) ?? 'json';
+
+      if (parseAs === 'stream') {
+        return opts.responseStyle === 'data'
+          ? response.body
+          : {
+              data: response.body,
+              ...result,
+            };
+      }
+
+      let data = await response[parseAs]();
+      if (parseAs === 'json') {
+        if (opts.responseValidator) {
+          await opts.responseValidator(data);
+        }
+
+        if (opts.responseTransformer) {
+          data = await opts.responseTransformer(data);
+        }
+      }
+
+      return opts.responseStyle === 'data'
+        ? data
+        : {
+            data,
+            ...result,
+          };
+    }
+
+    let error = await response.text();
+
+    try {
+      error = JSON.parse(error);
+    } catch {
+      // noop
+    }
+
+    let finalError = error;
+
+    for (const fn of interceptors.error._fns) {
+      if (fn) {
+        finalError = (await fn(error, response, request, opts)) as string;
+      }
+    }
+
+    finalError = finalError || ({} as string);
+
+    if (opts.throwOnError) {
+      throw finalError;
+    }
+
+    // TODO: we probably want to return error and improve types
+    return opts.responseStyle === 'data'
+      ? undefined
+      : {
+          error: finalError,
+          ...result,
+        };
+  };
+
+  return {
+    buildUrl,
+    connect: (options) => request({ ...options, method: 'CONNECT' }),
+    delete: (options) => request({ ...options, method: 'DELETE' }),
+    get: (options) => request({ ...options, method: 'GET' }),
+    getConfig,
+    head: (options) => request({ ...options, method: 'HEAD' }),
+    interceptors,
+    options: (options) => request({ ...options, method: 'OPTIONS' }),
+    patch: (options) => request({ ...options, method: 'PATCH' }),
+    post: (options) => request({ ...options, method: 'POST' }),
+    put: (options) => request({ ...options, method: 'PUT' }),
+    request,
+    setConfig,
+    trace: (options) => request({ ...options, method: 'TRACE' }),
+  };
+};

examples/openapi-ts-tanstack-react-query/src/client/client/index.ts

···
+export type { Auth } from '../core/auth';
+export type { QuerySerializerOptions } from '../core/bodySerializer';
+export {
+  formDataBodySerializer,
+  jsonBodySerializer,
+  urlSearchParamsBodySerializer,
+} from '../core/bodySerializer';
+export { buildClientParams } from '../core/params';
+export { createClient } from './client';
+export type {
+  Client,
+  ClientOptions,
+  Config,
+  CreateClientConfig,
+  Options,
+  OptionsLegacyParser,
+  RequestOptions,
+  RequestResult,
+  ResponseStyle,
+  TDataShape,
+} from './types';
+export { createConfig, mergeHeaders } from './utils';

examples/openapi-ts-tanstack-react-query/src/client/client/types.ts

···
+import type { Auth } from '../core/auth';
+import type { Client as CoreClient, Config as CoreConfig } from '../core/types';
+import type { Middleware } from './utils';
+
+export type ResponseStyle = 'data' | 'fields';
+
+export interface Config<T extends ClientOptions = ClientOptions>
+  extends Omit<RequestInit, 'body' | 'headers' | 'method'>,
+    CoreConfig {
+  /**
+   * Base URL for all requests made by this client.
+   */
+  baseUrl?: T['baseUrl'];
+  /**
+   * Fetch API implementation. You can use this option to provide a custom
+   * fetch instance.
+   *
+   * @default globalThis.fetch
+   */
+  fetch?: (request: Request) => ReturnType<typeof fetch>;
+  /**
+   * Please don't use the Fetch client for Next.js applications. The `next`
+   * options won't have any effect.
+   *
+   * Install {@link https://www.npmjs.com/package/@hey-api/client-next `@hey-api/client-next`} instead.
+   */
+  next?: never;
+  /**
+   * Return the response data parsed in a specified format. By default, `auto`
+   * will infer the appropriate method from the `Content-Type` response header.
+   * You can override this behavior with any of the {@link Body} methods.
+   * Select `stream` if you don't want to parse response data at all.
+   *
+   * @default 'auto'
+   */
+  parseAs?: Exclude<keyof Body, 'body' | 'bodyUsed'> | 'auto' | 'stream';
+  /**
+   * Should we return only data or multiple fields (data, error, response, etc.)?
+   *
+   * @default 'fields'
+   */
+  responseStyle?: ResponseStyle;
+  /**
+   * Throw an error instead of returning it in the response?
+   *
+   * @default false
+   */
+  throwOnError?: T['throwOnError'];
+}
+
+export interface RequestOptions<
+  TResponseStyle extends ResponseStyle = 'fields',
+  ThrowOnError extends boolean = boolean,
+  Url extends string = string,
+> extends Config<{
+    responseStyle: TResponseStyle;
+    throwOnError: ThrowOnError;
+  }> {
+  /**
+   * Any body that you want to add to your request.
+   *
+   * {@link https://developer.mozilla.org/docs/Web/API/fetch#body}
+   */
+  body?: unknown;
+  path?: Record<string, unknown>;
+  query?: Record<string, unknown>;
+  /**
+   * Security mechanism(s) to use for the request.
+   */
+  security?: ReadonlyArray<Auth>;
+  url: Url;
+}
+
+export type RequestResult<
+  TData = unknown,
+  TError = unknown,
+  ThrowOnError extends boolean = boolean,
+  TResponseStyle extends ResponseStyle = 'fields',
+> = ThrowOnError extends true
+  ? Promise<
+      TResponseStyle extends 'data'
+        ? TData extends Record<string, unknown>
+          ? TData[keyof TData]
+          : TData
+        : {
+            data: TData extends Record<string, unknown>
+              ? TData[keyof TData]
+              : TData;
+            request: Request;
+            response: Response;
+          }
+    >
+  : Promise<
+      TResponseStyle extends 'data'
+        ?
+            | (TData extends Record<string, unknown>
+                ? TData[keyof TData]
+                : TData)
+            | undefined
+        : (
+            | {
+                data: TData extends Record<string, unknown>
+                  ? TData[keyof TData]
+                  : TData;
+                error: undefined;
+              }
+            | {
+                data: undefined;
+                error: TError extends Record<string, unknown>
+                  ? TError[keyof TError]
+                  : TError;
+              }
+          ) & {
+            request: Request;
+            response: Response;
+          }
+    >;
+
+export interface ClientOptions {
+  baseUrl?: string;
+  responseStyle?: ResponseStyle;
+  throwOnError?: boolean;
+}
+
+type MethodFn = <
+  TData = unknown,
+  TError = unknown,
+  ThrowOnError extends boolean = false,
+  TResponseStyle extends ResponseStyle = 'fields',
+>(
+  options: Omit<RequestOptions<TResponseStyle, ThrowOnError>, 'method'>,
+) => RequestResult<TData, TError, ThrowOnError, TResponseStyle>;
+
+type RequestFn = <
+  TData = unknown,
+  TError = unknown,
+  ThrowOnError extends boolean = false,
+  TResponseStyle extends ResponseStyle = 'fields',
+>(
+  options: Omit<RequestOptions<TResponseStyle, ThrowOnError>, 'method'> &
+    Pick<Required<RequestOptions<TResponseStyle, ThrowOnError>>, 'method'>,
+) => RequestResult<TData, TError, ThrowOnError, TResponseStyle>;
+
+type BuildUrlFn = <
+  TData extends {
+    body?: unknown;
+    path?: Record<string, unknown>;
+    query?: Record<string, unknown>;
+    url: string;
+  },
+>(
+  options: Pick<TData, 'url'> & Options<TData>,
+) => string;
+
+export type Client = CoreClient<RequestFn, Config, MethodFn, BuildUrlFn> & {
+  interceptors: Middleware<Request, Response, unknown, RequestOptions>;
+};
+
+/**
+ * The `createClientConfig()` function will be called on client initialization
+ * and the returned object will become the client's initial configuration.
+ *
+ * You may want to initialize your client this way instead of calling
+ * `setConfig()`. This is useful for example if you're using Next.js
+ * to ensure your client always has the correct values.
+ */
+export type CreateClientConfig<T extends ClientOptions = ClientOptions> = (
+  override?: Config<ClientOptions & T>,
+) => Config<Required<ClientOptions> & T>;
+
+export interface TDataShape {
+  body?: unknown;
+  headers?: unknown;
+  path?: unknown;
+  query?: unknown;
+  url: string;
+}
+
+type OmitKeys<T, K> = Pick<T, Exclude<keyof T, K>>;
+
+export type Options<
+  TData extends TDataShape = TDataShape,
+  ThrowOnError extends boolean = boolean,
+  TResponseStyle extends ResponseStyle = 'fields',
+> = OmitKeys<
+  RequestOptions<TResponseStyle, ThrowOnError>,
+  'body' | 'path' | 'query' | 'url'
+> &
+  Omit<TData, 'url'>;
+
+export type OptionsLegacyParser<
+  TData = unknown,
+  ThrowOnError extends boolean = boolean,
+  TResponseStyle extends ResponseStyle = 'fields',
+> = TData extends { body?: any }
+  ? TData extends { headers?: any }
+    ? OmitKeys<
+        RequestOptions<TResponseStyle, ThrowOnError>,
+        'body' | 'headers' | 'url'
+      > &
+        TData
+    : OmitKeys<RequestOptions<TResponseStyle, ThrowOnError>, 'body' | 'url'> &
+        TData &
+        Pick<RequestOptions<TResponseStyle, ThrowOnError>, 'headers'>
+  : TData extends { headers?: any }
+    ? OmitKeys<
+        RequestOptions<TResponseStyle, ThrowOnError>,
+        'headers' | 'url'
+      > &
+        TData &
+        Pick<RequestOptions<TResponseStyle, ThrowOnError>, 'body'>
+    : OmitKeys<RequestOptions<TResponseStyle, ThrowOnError>, 'url'> & TData;

examples/openapi-ts-tanstack-react-query/src/client/client/utils.ts

···
+import { getAuthToken } from '../core/auth';
+import type {
+  QuerySerializer,
+  QuerySerializerOptions,
+} from '../core/bodySerializer';
+import { jsonBodySerializer } from '../core/bodySerializer';
+import {
+  serializeArrayParam,
+  serializeObjectParam,
+  serializePrimitiveParam,
+} from '../core/pathSerializer';
+import type { Client, ClientOptions, Config, RequestOptions } from './types';
+
+interface PathSerializer {
+  path: Record<string, unknown>;
+  url: string;
+}
+
+const PATH_PARAM_RE = /\{[^{}]+\}/g;
+
+type ArrayStyle = 'form' | 'spaceDelimited' | 'pipeDelimited';
+type MatrixStyle = 'label' | 'matrix' | 'simple';
+type ArraySeparatorStyle = ArrayStyle | MatrixStyle;
+
+const defaultPathSerializer = ({ path, url: _url }: PathSerializer) => {
+  let url = _url;
+  const matches = _url.match(PATH_PARAM_RE);
+  if (matches) {
+    for (const match of matches) {
+      let explode = false;
+      let name = match.substring(1, match.length - 1);
+      let style: ArraySeparatorStyle = 'simple';
+
+      if (name.endsWith('*')) {
+        explode = true;
+        name = name.substring(0, name.length - 1);
+      }
+
+      if (name.startsWith('.')) {
+        name = name.substring(1);
+        style = 'label';
+      } else if (name.startsWith(';')) {
+        name = name.substring(1);
+        style = 'matrix';
+      }
+
+      const value = path[name];
+
+      if (value === undefined || value === null) {
+        continue;
+      }
+
+      if (Array.isArray(value)) {
+        url = url.replace(
+          match,
+          serializeArrayParam({ explode, name, style, value }),
+        );
+        continue;
+      }
+
+      if (typeof value === 'object') {
+        url = url.replace(
+          match,
+          serializeObjectParam({
+            explode,
+            name,
+            style,
+            value: value as Record<string, unknown>,
+            valueOnly: true,
+          }),
+        );
+        continue;
+      }
+
+      if (style === 'matrix') {
+        url = url.replace(
+          match,
+          `;${serializePrimitiveParam({
+            name,
+            value: value as string,
+          })}`,
+        );
+        continue;
+      }
+
+      const replaceValue = encodeURIComponent(
+        style === 'label' ? `.${value as string}` : (value as string),
+      );
+      url = url.replace(match, replaceValue);
+    }
+  }
+  return url;
+};
+
+export const createQuerySerializer = <T = unknown>({
+  allowReserved,
+  array,
+  object,
+}: QuerySerializerOptions = {}) => {
+  const querySerializer = (queryParams: T) => {
+    const search: string[] = [];
+    if (queryParams && typeof queryParams === 'object') {
+      for (const name in queryParams) {
+        const value = queryParams[name];
+
+        if (value === undefined || value === null) {
+          continue;
+        }
+
+        if (Array.isArray(value)) {
+          const serializedArray = serializeArrayParam({
+            allowReserved,
+            explode: true,
+            name,
+            style: 'form',
+            value,
+            ...array,
+          });
+          if (serializedArray) search.push(serializedArray);
+        } else if (typeof value === 'object') {
+          const serializedObject = serializeObjectParam({
+            allowReserved,
+            explode: true,
+            name,
+            style: 'deepObject',
+            value: value as Record<string, unknown>,
+            ...object,
+          });
+          if (serializedObject) search.push(serializedObject);
+        } else {
+          const serializedPrimitive = serializePrimitiveParam({
+            allowReserved,
+            name,
+            value: value as string,
+          });
+          if (serializedPrimitive) search.push(serializedPrimitive);
+        }
+      }
+    }
+    return search.join('&');
+  };
+  return querySerializer;
+};
+
+/**
+ * Infers parseAs value from provided Content-Type header.
+ */
+export const getParseAs = (
+  contentType: string | null,
+): Exclude<Config['parseAs'], 'auto'> => {
+  if (!contentType) {
+    // If no Content-Type header is provided, the best we can do is return the raw response body,
+    // which is effectively the same as the 'stream' option.
+    return 'stream';
+  }
+
+  const cleanContent = contentType.split(';')[0]?.trim();
+
+  if (!cleanContent) {
+    return;
+  }
+
+  if (
+    cleanContent.startsWith('application/json') ||
+    cleanContent.endsWith('+json')
+  ) {
+    return 'json';
+  }
+
+  if (cleanContent === 'multipart/form-data') {
+    return 'formData';
+  }
+
+  if (
+    ['application/', 'audio/', 'image/', 'video/'].some((type) =>
+      cleanContent.startsWith(type),
+    )
+  ) {
+    return 'blob';
+  }
+
+  if (cleanContent.startsWith('text/')) {
+    return 'text';
+  }
+};
+
+export const setAuthParams = async ({
+  security,
+  ...options
+}: Pick<Required<RequestOptions>, 'security'> &
+  Pick<RequestOptions, 'auth' | 'query'> & {
+    headers: Headers;
+  }) => {
+  for (const auth of security) {
+    const token = await getAuthToken(auth, options.auth);
+
+    if (!token) {
+      continue;
+    }
+
+    const name = auth.name ?? 'Authorization';
+
+    switch (auth.in) {
+      case 'query':
+        if (!options.query) {
+          options.query = {};
+        }
+        options.query[name] = token;
+        break;
+      case 'cookie':
+        options.headers.append('Cookie', `${name}=${token}`);
+        break;
+      case 'header':
+      default:
+        options.headers.set(name, token);
+        break;
+    }
+
+    return;
+  }
+};
+
+export const buildUrl: Client['buildUrl'] = (options) => {
+  const url = getUrl({
+    baseUrl: options.baseUrl as string,
+    path: options.path,
+    query: options.query,
+    querySerializer:
+      typeof options.querySerializer === 'function'
+        ? options.querySerializer
+        : createQuerySerializer(options.querySerializer),
+    url: options.url,
+  });
+  return url;
+};
+
+export const getUrl = ({
+  baseUrl,
+  path,
+  query,
+  querySerializer,
+  url: _url,
+}: {
+  baseUrl?: string;
+  path?: Record<string, unknown>;
+  query?: Record<string, unknown>;
+  querySerializer: QuerySerializer;
+  url: string;
+}) => {
+  const pathUrl = _url.startsWith('/') ? _url : `/${_url}`;
+  let url = (baseUrl ?? '') + pathUrl;
+  if (path) {
+    url = defaultPathSerializer({ path, url });
+  }
+  let search = query ? querySerializer(query) : '';
+  if (search.startsWith('?')) {
+    search = search.substring(1);
+  }
+  if (search) {
+    url += `?${search}`;
+  }
+  return url;
+};
+
+export const mergeConfigs = (a: Config, b: Config): Config => {
+  const config = { ...a, ...b };
+  if (config.baseUrl?.endsWith('/')) {
+    config.baseUrl = config.baseUrl.substring(0, config.baseUrl.length - 1);
+  }
+  config.headers = mergeHeaders(a.headers, b.headers);
+  return config;
+};
+
+export const mergeHeaders = (
+  ...headers: Array<Required<Config>['headers'] | undefined>
+): Headers => {
+  const mergedHeaders = new Headers();
+  for (const header of headers) {
+    if (!header || typeof header !== 'object') {
+      continue;
+    }
+
+    const iterator =
+      header instanceof Headers ? header.entries() : Object.entries(header);
+
+    for (const [key, value] of iterator) {
+      if (value === null) {
+        mergedHeaders.delete(key);
+      } else if (Array.isArray(value)) {
+        for (const v of value) {
+          mergedHeaders.append(key, v as string);
+        }
+      } else if (value !== undefined) {
+        // assume object headers are meant to be JSON stringified, i.e. their
+        // content value in OpenAPI specification is 'application/json'
+        mergedHeaders.set(
+          key,
+          typeof value === 'object' ? JSON.stringify(value) : (value as string),
+        );
+      }
+    }
+  }
+  return mergedHeaders;
+};
+
+type ErrInterceptor<Err, Res, Req, Options> = (
+  error: Err,
+  response: Res,
+  request: Req,
+  options: Options,
+) => Err | Promise<Err>;
+
+type ReqInterceptor<Req, Options> = (
+  request: Req,
+  options: Options,
+) => Req | Promise<Req>;
+
+type ResInterceptor<Res, Req, Options> = (
+  response: Res,
+  request: Req,
+  options: Options,
+) => Res | Promise<Res>;
+
+class Interceptors<Interceptor> {
+  _fns: (Interceptor | null)[];
+
+  constructor() {
+    this._fns = [];
+  }
+
+  clear() {
+    this._fns = [];
+  }
+
+  getInterceptorIndex(id: number | Interceptor): number {
+    if (typeof id === 'number') {
+      return this._fns[id] ? id : -1;
+    } else {
+      return this._fns.indexOf(id);
+    }
+  }
+  exists(id: number | Interceptor) {
+    const index = this.getInterceptorIndex(id);
+    return !!this._fns[index];
+  }
+
+  eject(id: number | Interceptor) {
+    const index = this.getInterceptorIndex(id);
+    if (this._fns[index]) {
+      this._fns[index] = null;
+    }
+  }
+
+  update(id: number | Interceptor, fn: Interceptor) {
+    const index = this.getInterceptorIndex(id);
+    if (this._fns[index]) {
+      this._fns[index] = fn;
+      return id;
+    } else {
+      return false;
+    }
+  }
+
+  use(fn: Interceptor) {
+    this._fns = [...this._fns, fn];
+    return this._fns.length - 1;
+  }
+}
+
+// `createInterceptors()` response, meant for external use as it does not
+// expose internals
+export interface Middleware<Req, Res, Err, Options> {
+  error: Pick<
+    Interceptors<ErrInterceptor<Err, Res, Req, Options>>,
+    'eject' | 'use'
+  >;
+  request: Pick<Interceptors<ReqInterceptor<Req, Options>>, 'eject' | 'use'>;
+  response: Pick<
+    Interceptors<ResInterceptor<Res, Req, Options>>,
+    'eject' | 'use'
+  >;
+}
+
+// do not add `Middleware` as return type so we can use _fns internally
+export const createInterceptors = <Req, Res, Err, Options>() => ({
+  error: new Interceptors<ErrInterceptor<Err, Res, Req, Options>>(),
+  request: new Interceptors<ReqInterceptor<Req, Options>>(),
+  response: new Interceptors<ResInterceptor<Res, Req, Options>>(),
+});
+
+const defaultQuerySerializer = createQuerySerializer({
+  allowReserved: false,
+  array: {
+    explode: true,
+    style: 'form',
+  },
+  object: {
+    explode: true,
+    style: 'deepObject',
+  },
+});
+
+const defaultHeaders = {
+  'Content-Type': 'application/json',
+};
+
+export const createConfig = <T extends ClientOptions = ClientOptions>(
+  override: Config<Omit<ClientOptions, keyof T> & T> = {},
+): Config<Omit<ClientOptions, keyof T> & T> => ({
+  ...jsonBodySerializer,
+  headers: defaultHeaders,
+  parseAs: 'auto',
+  querySerializer: defaultQuerySerializer,
+  ...override,
+});

examples/openapi-ts-tanstack-react-query/src/client/core/auth.ts

···
+export type AuthToken = string | undefined;
+
+export interface Auth {
+  /**
+   * Which part of the request do we use to send the auth?
+   *
+   * @default 'header'
+   */
+  in?: 'header' | 'query' | 'cookie';
+  /**
+   * Header or query parameter name.
+   *
+   * @default 'Authorization'
+   */
+  name?: string;
+  scheme?: 'basic' | 'bearer';
+  type: 'apiKey' | 'http';
+}
+
+export const getAuthToken = async (
+  auth: Auth,
+  callback: ((auth: Auth) => Promise<AuthToken> | AuthToken) | AuthToken,
+): Promise<string | undefined> => {
+  const token =
+    typeof callback === 'function' ? await callback(auth) : callback;
+
+  if (!token) {
+    return;
+  }
+
+  if (auth.scheme === 'bearer') {
+    return `Bearer ${token}`;
+  }
+
+  if (auth.scheme === 'basic') {
+    return `Basic ${btoa(token)}`;
+  }
+
+  return token;
+};

examples/openapi-ts-tanstack-react-query/src/client/core/bodySerializer.ts

···
+import type {
+  ArrayStyle,
+  ObjectStyle,
+  SerializerOptions,
+} from './pathSerializer';
+
+export type QuerySerializer = (query: Record<string, unknown>) => string;
+
+export type BodySerializer = (body: any) => any;
+
+export interface QuerySerializerOptions {
+  allowReserved?: boolean;
+  array?: SerializerOptions<ArrayStyle>;
+  object?: SerializerOptions<ObjectStyle>;
+}
+
+const serializeFormDataPair = (data: FormData, key: string, value: unknown) => {
+  if (typeof value === 'string' || value instanceof Blob) {
+    data.append(key, value);
+  } else {
+    data.append(key, JSON.stringify(value));
+  }
+};
+
+const serializeUrlSearchParamsPair = (
+  data: URLSearchParams,
+  key: string,
+  value: unknown,
+) => {
+  if (typeof value === 'string') {
+    data.append(key, value);
+  } else {
+    data.append(key, JSON.stringify(value));
+  }
+};
+
+export const formDataBodySerializer = {
+  bodySerializer: <T extends Record<string, any> | Array<Record<string, any>>>(
+    body: T,
+  ) => {
+    const data = new FormData();
+
+    Object.entries(body).forEach(([key, value]) => {
+      if (value === undefined || value === null) {
+        return;
+      }
+      if (Array.isArray(value)) {
+        value.forEach((v) => serializeFormDataPair(data, key, v));
+      } else {
+        serializeFormDataPair(data, key, value);
+      }
+    });
+
+    return data;
+  },
+};
+
+export const jsonBodySerializer = {
+  bodySerializer: <T>(body: T) =>
+    JSON.stringify(body, (key, value) =>
+      typeof value === 'bigint' ? value.toString() : value,
+    ),
+};
+
+export const urlSearchParamsBodySerializer = {
+  bodySerializer: <T extends Record<string, any> | Array<Record<string, any>>>(
+    body: T,
+  ) => {
+    const data = new URLSearchParams();
+
+    Object.entries(body).forEach(([key, value]) => {
+      if (value === undefined || value === null) {
+        return;
+      }
+      if (Array.isArray(value)) {
+        value.forEach((v) => serializeUrlSearchParamsPair(data, key, v));
+      } else {
+        serializeUrlSearchParamsPair(data, key, value);
+      }
+    });
+
+    return data.toString();
+  },
+};

examples/openapi-ts-tanstack-react-query/src/client/core/params.ts

···
+type Slot = 'body' | 'headers' | 'path' | 'query';
+
+export type Field =
+  | {
+      in: Exclude<Slot, 'body'>;
+      key: string;
+      map?: string;
+    }
+  | {
+      in: Extract<Slot, 'body'>;
+      key?: string;
+      map?: string;
+    };
+
+export interface Fields {
+  allowExtra?: Partial<Record<Slot, boolean>>;
+  args?: ReadonlyArray<Field>;
+}
+
+export type FieldsConfig = ReadonlyArray<Field | Fields>;
+
+const extraPrefixesMap: Record<string, Slot> = {
+  $body_: 'body',
+  $headers_: 'headers',
+  $path_: 'path',
+  $query_: 'query',
+};
+const extraPrefixes = Object.entries(extraPrefixesMap);
+
+type KeyMap = Map<
+  string,
+  {
+    in: Slot;
+    map?: string;
+  }
+>;
+
+const buildKeyMap = (fields: FieldsConfig, map?: KeyMap): KeyMap => {
+  if (!map) {
+    map = new Map();
+  }
+
+  for (const config of fields) {
+    if ('in' in config) {
+      if (config.key) {
+        map.set(config.key, {
+          in: config.in,
+          map: config.map,
+        });
+      }
+    } else if (config.args) {
+      buildKeyMap(config.args, map);
+    }
+  }
+
+  return map;
+};
+
+interface Params {
+  body: unknown;
+  headers: Record<string, unknown>;
+  path: Record<string, unknown>;
+  query: Record<string, unknown>;
+}
+
+const stripEmptySlots = (params: Params) => {
+  for (const [slot, value] of Object.entries(params)) {
+    if (value && typeof value === 'object' && !Object.keys(value).length) {
+      delete params[slot as Slot];
+    }
+  }
+};
+
+export const buildClientParams = (
+  args: ReadonlyArray<unknown>,
+  fields: FieldsConfig,
+) => {
+  const params: Params = {
+    body: {},
+    headers: {},
+    path: {},
+    query: {},
+  };
+
+  const map = buildKeyMap(fields);
+
+  let config: FieldsConfig[number] | undefined;
+
+  for (const [index, arg] of args.entries()) {
+    if (fields[index]) {
+      config = fields[index];
+    }
+
+    if (!config) {
+      continue;
+    }
+
+    if ('in' in config) {
+      if (config.key) {
+        const field = map.get(config.key)!;
+        const name = field.map || config.key;
+        (params[field.in] as Record<string, unknown>)[name] = arg;
+      } else {
+        params.body = arg;
+      }
+    } else {
+      for (const [key, value] of Object.entries(arg ?? {})) {
+        const field = map.get(key);
+
+        if (field) {
+          const name = field.map || key;
+          (params[field.in] as Record<string, unknown>)[name] = value;
+        } else {
+          const extra = extraPrefixes.find(([prefix]) =>
+            key.startsWith(prefix),
+          );
+
+          if (extra) {
+            const [prefix, slot] = extra;
+            (params[slot] as Record<string, unknown>)[
+              key.slice(prefix.length)
+            ] = value;
+          } else {
+            for (const [slot, allowed] of Object.entries(
+              config.allowExtra ?? {},
+            )) {
+              if (allowed) {
+                (params[slot as Slot] as Record<string, unknown>)[key] = value;
+                break;
+              }
+            }
+          }
+        }
+      }
+    }
+  }
+
+  stripEmptySlots(params);
+
+  return params;
+};

examples/openapi-ts-tanstack-react-query/src/client/core/pathSerializer.ts

···
+interface SerializeOptions<T>
+  extends SerializePrimitiveOptions,
+    SerializerOptions<T> {}
+
+interface SerializePrimitiveOptions {
+  allowReserved?: boolean;
+  name: string;
+}
+
+export interface SerializerOptions<T> {
+  /**
+   * @default true
+   */
+  explode: boolean;
+  style: T;
+}
+
+export type ArrayStyle = 'form' | 'spaceDelimited' | 'pipeDelimited';
+export type ArraySeparatorStyle = ArrayStyle | MatrixStyle;
+type MatrixStyle = 'label' | 'matrix' | 'simple';
+export type ObjectStyle = 'form' | 'deepObject';
+type ObjectSeparatorStyle = ObjectStyle | MatrixStyle;
+
+interface SerializePrimitiveParam extends SerializePrimitiveOptions {
+  value: string;
+}
+
+export const separatorArrayExplode = (style: ArraySeparatorStyle) => {
+  switch (style) {
+    case 'label':
+      return '.';
+    case 'matrix':
+      return ';';
+    case 'simple':
+      return ',';
+    default:
+      return '&';
+  }
+};
+
+export const separatorArrayNoExplode = (style: ArraySeparatorStyle) => {
+  switch (style) {
+    case 'form':
+      return ',';
+    case 'pipeDelimited':
+      return '|';
+    case 'spaceDelimited':
+      return '%20';
+    default:
+      return ',';
+  }
+};
+
+export const separatorObjectExplode = (style: ObjectSeparatorStyle) => {
+  switch (style) {
+    case 'label':
+      return '.';
+    case 'matrix':
+      return ';';
+    case 'simple':
+      return ',';
+    default:
+      return '&';
+  }
+};
+
+export const serializeArrayParam = ({
+  allowReserved,
+  explode,
+  name,
+  style,
+  value,
+}: SerializeOptions<ArraySeparatorStyle> & {
+  value: unknown[];
+}) => {
+  if (!explode) {
+    const joinedValues = (
+      allowReserved ? value : value.map((v) => encodeURIComponent(v as string))
+    ).join(separatorArrayNoExplode(style));
+    switch (style) {
+      case 'label':
+        return `.${joinedValues}`;
+      case 'matrix':
+        return `;${name}=${joinedValues}`;
+      case 'simple':
+        return joinedValues;
+      default:
+        return `${name}=${joinedValues}`;
+    }
+  }
+
+  const separator = separatorArrayExplode(style);
+  const joinedValues = value
+    .map((v) => {
+      if (style === 'label' || style === 'simple') {
+        return allowReserved ? v : encodeURIComponent(v as string);
+      }
+
+      return serializePrimitiveParam({
+        allowReserved,
+        name,
+        value: v as string,
+      });
+    })
+    .join(separator);
+  return style === 'label' || style === 'matrix'
+    ? separator + joinedValues
+    : joinedValues;
+};
+
+export const serializePrimitiveParam = ({
+  allowReserved,
+  name,
+  value,
+}: SerializePrimitiveParam) => {
+  if (value === undefined || value === null) {
+    return '';
+  }
+
+  if (typeof value === 'object') {
+    throw new Error(
+      'Deeply-nested arrays/objects aren’t supported. Provide your own `querySerializer()` to handle these.',
+    );
+  }
+
+  return `${name}=${allowReserved ? value : encodeURIComponent(value)}`;
+};
+
+export const serializeObjectParam = ({
+  allowReserved,
+  explode,
+  name,
+  style,
+  value,
+  valueOnly,
+}: SerializeOptions<ObjectSeparatorStyle> & {
+  value: Record<string, unknown> | Date;
+  valueOnly?: boolean;
+}) => {
+  if (value instanceof Date) {
+    return valueOnly ? value.toISOString() : `${name}=${value.toISOString()}`;
+  }
+
+  if (style !== 'deepObject' && !explode) {
+    let values: string[] = [];
+    Object.entries(value).forEach(([key, v]) => {
+      values = [
+        ...values,
+        key,
+        allowReserved ? (v as string) : encodeURIComponent(v as string),
+      ];
+    });
+    const joinedValues = values.join(',');
+    switch (style) {
+      case 'form':
+        return `${name}=${joinedValues}`;
+      case 'label':
+        return `.${joinedValues}`;
+      case 'matrix':
+        return `;${name}=${joinedValues}`;
+      default:
+        return joinedValues;
+    }
+  }
+
+  const separator = separatorObjectExplode(style);
+  const joinedValues = Object.entries(value)
+    .map(([key, v]) =>
+      serializePrimitiveParam({
+        allowReserved,
+        name: style === 'deepObject' ? `${name}[${key}]` : key,
+        value: v as string,
+      }),
+    )
+    .join(separator);
+  return style === 'label' || style === 'matrix'
+    ? separator + joinedValues
+    : joinedValues;
+};

examples/openapi-ts-tanstack-react-query/src/client/core/types.ts

···
+import type { Auth, AuthToken } from './auth';
+import type {
+  BodySerializer,
+  QuerySerializer,
+  QuerySerializerOptions,
+} from './bodySerializer';
+
+export interface Client<
+  RequestFn = never,
+  Config = unknown,
+  MethodFn = never,
+  BuildUrlFn = never,
+> {
+  /**
+   * Returns the final request URL.
+   */
+  buildUrl: BuildUrlFn;
+  connect: MethodFn;
+  delete: MethodFn;
+  get: MethodFn;
+  getConfig: () => Config;
+  head: MethodFn;
+  options: MethodFn;
+  patch: MethodFn;
+  post: MethodFn;
+  put: MethodFn;
+  request: RequestFn;
+  setConfig: (config: Config) => Config;
+  trace: MethodFn;
+}
+
+export interface Config {
+  /**
+   * Auth token or a function returning auth token. The resolved value will be
+   * added to the request payload as defined by its `security` array.
+   */
+  auth?: ((auth: Auth) => Promise<AuthToken> | AuthToken) | AuthToken;
+  /**
+   * A function for serializing request body parameter. By default,
+   * {@link JSON.stringify()} will be used.
+   */
+  bodySerializer?: BodySerializer | null;
+  /**
+   * An object containing any HTTP headers that you want to pre-populate your
+   * `Headers` object with.
+   *
+   * {@link https://developer.mozilla.org/docs/Web/API/Headers/Headers#init See more}
+   */
+  headers?:
+    | RequestInit['headers']
+    | Record<
+        string,
+        | string
+        | number
+        | boolean
+        | (string | number | boolean)[]
+        | null
+        | undefined
+        | unknown
+      >;
+  /**
+   * The request method.
+   *
+   * {@link https://developer.mozilla.org/docs/Web/API/fetch#method See more}
+   */
+  method?:
+    | 'CONNECT'
+    | 'DELETE'
+    | 'GET'
+    | 'HEAD'
+    | 'OPTIONS'
+    | 'PATCH'
+    | 'POST'
+    | 'PUT'
+    | 'TRACE';
+  /**
+   * A function for serializing request query parameters. By default, arrays
+   * will be exploded in form style, objects will be exploded in deepObject
+   * style, and reserved characters are percent-encoded.
+   *
+   * This method will have no effect if the native `paramsSerializer()` Axios
+   * API function is used.
+   *
+   * {@link https://swagger.io/docs/specification/serialization/#query View examples}
+   */
+  querySerializer?: QuerySerializer | QuerySerializerOptions;
+  /**
+   * A function transforming response data before it's returned. This is useful
+   * for post-processing data, e.g. converting ISO strings into Date objects.
+   */
+  responseTransformer?: (data: unknown) => Promise<unknown>;
+  /**
+   * A function validating response data. This is useful if you want to ensure
+   * the response conforms to the desired shape, so it can be safely passed to
+   * the transformers and returned to the user.
+   */
+  responseValidator?: (data: unknown) => Promise<unknown>;
+}

examples/openapi-ts-tanstack-react-query/src/client/sdk.gen.ts

···
 // This file is auto-generated by @hey-api/openapi-ts
 
-import type {
-  Client,
-  Options as ClientOptions,
-  TDataShape,
-} from '@hey-api/client-fetch';
-
+import type { Client, Options as ClientOptions, TDataShape } from './client';
 import { client as _heyApiClient } from './client.gen';
 import type {
   AddPetData,
···
     ...options,
     headers: {
       'Content-Type': 'application/json',
-      ...options?.headers,
+      ...options.headers,
     },
   });
 
···
     ...options,
     headers: {
       'Content-Type': 'application/json',
-      ...options?.headers,
+      ...options.headers,
     },
   });
 
···
     ...options,
     headers: {
       'Content-Type': 'application/octet-stream',
-      ...options?.headers,
+      ...options.headers,
     },
   });
 
···
     ...options,
     headers: {
       'Content-Type': 'application/json',
-      ...options?.headers,
+      ...options.headers,
     },
   });

examples/openapi-ts-tanstack-svelte-query/package.json

···
     "test": "vitest --watch=false"
   },
   "dependencies": {
-    "@hey-api/client-fetch": "workspace:*",
     "@tanstack/svelte-query": "5.73.3"
   },
   "devDependencies": {

examples/openapi-ts-tanstack-svelte-query/src/client/client.gen.ts

···
   type Config,
   createClient,
   createConfig,
-} from '@hey-api/client-fetch';
-
+} from './client';
 import type { ClientOptions } from './types.gen';
 
 /**

examples/openapi-ts-tanstack-svelte-query/src/client/client/client.ts

···
+import type { Client, Config, RequestOptions } from './types';
+import {
+  buildUrl,
+  createConfig,
+  createInterceptors,
+  getParseAs,
+  mergeConfigs,
+  mergeHeaders,
+  setAuthParams,
+} from './utils';
+
+type ReqInit = Omit<RequestInit, 'body' | 'headers'> & {
+  body?: any;
+  headers: ReturnType<typeof mergeHeaders>;
+};
+
+export const createClient = (config: Config = {}): Client => {
+  let _config = mergeConfigs(createConfig(), config);
+
+  const getConfig = (): Config => ({ ..._config });
+
+  const setConfig = (config: Config): Config => {
+    _config = mergeConfigs(_config, config);
+    return getConfig();
+  };
+
+  const interceptors = createInterceptors<
+    Request,
+    Response,
+    unknown,
+    RequestOptions
+  >();
+
+  const request: Client['request'] = async (options) => {
+    const opts = {
+      ..._config,
+      ...options,
+      fetch: options.fetch ?? _config.fetch ?? globalThis.fetch,
+      headers: mergeHeaders(_config.headers, options.headers),
+    };
+
+    if (opts.security) {
+      await setAuthParams({
+        ...opts,
+        security: opts.security,
+      });
+    }
+
+    if (opts.body && opts.bodySerializer) {
+      opts.body = opts.bodySerializer(opts.body);
+    }
+
+    // remove Content-Type header if body is empty to avoid sending invalid requests
+    if (opts.body === undefined || opts.body === '') {
+      opts.headers.delete('Content-Type');
+    }
+
+    const url = buildUrl(opts);
+    const requestInit: ReqInit = {
+      redirect: 'follow',
+      ...opts,
+    };
+
+    let request = new Request(url, requestInit);
+
+    for (const fn of interceptors.request._fns) {
+      if (fn) {
+        request = await fn(request, opts);
+      }
+    }
+
+    // fetch must be assigned here, otherwise it would throw the error:
+    // TypeError: Failed to execute 'fetch' on 'Window': Illegal invocation
+    const _fetch = opts.fetch!;
+    let response = await _fetch(request);
+
+    for (const fn of interceptors.response._fns) {
+      if (fn) {
+        response = await fn(response, request, opts);
+      }
+    }
+
+    const result = {
+      request,
+      response,
+    };
+
+    if (response.ok) {
+      if (
+        response.status === 204 ||
+        response.headers.get('Content-Length') === '0'
+      ) {
+        return opts.responseStyle === 'data'
+          ? {}
+          : {
+              data: {},
+              ...result,
+            };
+      }
+
+      const parseAs =
+        (opts.parseAs === 'auto'
+          ? getParseAs(response.headers.get('Content-Type'))
+          : opts.parseAs) ?? 'json';
+
+      if (parseAs === 'stream') {
+        return opts.responseStyle === 'data'
+          ? response.body
+          : {
+              data: response.body,
+              ...result,
+            };
+      }
+
+      let data = await response[parseAs]();
+      if (parseAs === 'json') {
+        if (opts.responseValidator) {
+          await opts.responseValidator(data);
+        }
+
+        if (opts.responseTransformer) {
+          data = await opts.responseTransformer(data);
+        }
+      }
+
+      return opts.responseStyle === 'data'
+        ? data
+        : {
+            data,
+            ...result,
+          };
+    }
+
+    let error = await response.text();
+
+    try {
+      error = JSON.parse(error);
+    } catch {
+      // noop
+    }
+
+    let finalError = error;
+
+    for (const fn of interceptors.error._fns) {
+      if (fn) {
+        finalError = (await fn(error, response, request, opts)) as string;
+      }
+    }
+
+    finalError = finalError || ({} as string);
+
+    if (opts.throwOnError) {
+      throw finalError;
+    }
+
+    // TODO: we probably want to return error and improve types
+    return opts.responseStyle === 'data'
+      ? undefined
+      : {
+          error: finalError,
+          ...result,
+        };
+  };
+
+  return {
+    buildUrl,
+    connect: (options) => request({ ...options, method: 'CONNECT' }),
+    delete: (options) => request({ ...options, method: 'DELETE' }),
+    get: (options) => request({ ...options, method: 'GET' }),
+    getConfig,
+    head: (options) => request({ ...options, method: 'HEAD' }),
+    interceptors,
+    options: (options) => request({ ...options, method: 'OPTIONS' }),
+    patch: (options) => request({ ...options, method: 'PATCH' }),
+    post: (options) => request({ ...options, method: 'POST' }),
+    put: (options) => request({ ...options, method: 'PUT' }),
+    request,
+    setConfig,
+    trace: (options) => request({ ...options, method: 'TRACE' }),
+  };
+};

examples/openapi-ts-tanstack-svelte-query/src/client/client/index.ts

···
+export type { Auth } from '../core/auth';
+export type { QuerySerializerOptions } from '../core/bodySerializer';
+export {
+  formDataBodySerializer,
+  jsonBodySerializer,
+  urlSearchParamsBodySerializer,
+} from '../core/bodySerializer';
+export { buildClientParams } from '../core/params';
+export { createClient } from './client';
+export type {
+  Client,
+  ClientOptions,
+  Config,
+  CreateClientConfig,
+  Options,
+  OptionsLegacyParser,
+  RequestOptions,
+  RequestResult,
+  ResponseStyle,
+  TDataShape,
+} from './types';
+export { createConfig, mergeHeaders } from './utils';

examples/openapi-ts-tanstack-svelte-query/src/client/client/types.ts

···
+import type { Auth } from '../core/auth';
+import type { Client as CoreClient, Config as CoreConfig } from '../core/types';
+import type { Middleware } from './utils';
+
+export type ResponseStyle = 'data' | 'fields';
+
+export interface Config<T extends ClientOptions = ClientOptions>
+  extends Omit<RequestInit, 'body' | 'headers' | 'method'>,
+    CoreConfig {
+  /**
+   * Base URL for all requests made by this client.
+   */
+  baseUrl?: T['baseUrl'];
+  /**
+   * Fetch API implementation. You can use this option to provide a custom
+   * fetch instance.
+   *
+   * @default globalThis.fetch
+   */
+  fetch?: (request: Request) => ReturnType<typeof fetch>;
+  /**
+   * Please don't use the Fetch client for Next.js applications. The `next`
+   * options won't have any effect.
+   *
+   * Install {@link https://www.npmjs.com/package/@hey-api/client-next `@hey-api/client-next`} instead.
+   */
+  next?: never;
+  /**
+   * Return the response data parsed in a specified format. By default, `auto`
+   * will infer the appropriate method from the `Content-Type` response header.
+   * You can override this behavior with any of the {@link Body} methods.
+   * Select `stream` if you don't want to parse response data at all.
+   *
+   * @default 'auto'
+   */
+  parseAs?: Exclude<keyof Body, 'body' | 'bodyUsed'> | 'auto' | 'stream';
+  /**
+   * Should we return only data or multiple fields (data, error, response, etc.)?
+   *
+   * @default 'fields'
+   */
+  responseStyle?: ResponseStyle;
+  /**
+   * Throw an error instead of returning it in the response?
+   *
+   * @default false
+   */
+  throwOnError?: T['throwOnError'];
+}
+
+export interface RequestOptions<
+  TResponseStyle extends ResponseStyle = 'fields',
+  ThrowOnError extends boolean = boolean,
+  Url extends string = string,
+> extends Config<{
+    responseStyle: TResponseStyle;
+    throwOnError: ThrowOnError;
+  }> {
+  /**
+   * Any body that you want to add to your request.
+   *
+   * {@link https://developer.mozilla.org/docs/Web/API/fetch#body}
+   */
+  body?: unknown;
+  path?: Record<string, unknown>;
+  query?: Record<string, unknown>;
+  /**
+   * Security mechanism(s) to use for the request.
+   */
+  security?: ReadonlyArray<Auth>;
+  url: Url;
+}
+
+export type RequestResult<
+  TData = unknown,
+  TError = unknown,
+  ThrowOnError extends boolean = boolean,
+  TResponseStyle extends ResponseStyle = 'fields',
+> = ThrowOnError extends true
+  ? Promise<
+      TResponseStyle extends 'data'
+        ? TData extends Record<string, unknown>
+          ? TData[keyof TData]
+          : TData
+        : {
+            data: TData extends Record<string, unknown>
+              ? TData[keyof TData]
+              : TData;
+            request: Request;
+            response: Response;
+          }
+    >
+  : Promise<
+      TResponseStyle extends 'data'
+        ?
+            | (TData extends Record<string, unknown>
+                ? TData[keyof TData]
+                : TData)
+            | undefined
+        : (
+            | {
+                data: TData extends Record<string, unknown>
+                  ? TData[keyof TData]
+                  : TData;
+                error: undefined;
+              }
+            | {
+                data: undefined;
+                error: TError extends Record<string, unknown>
+                  ? TError[keyof TError]
+                  : TError;
+              }
+          ) & {
+            request: Request;
+            response: Response;
+          }
+    >;
+
+export interface ClientOptions {
+  baseUrl?: string;
+  responseStyle?: ResponseStyle;
+  throwOnError?: boolean;
+}
+
+type MethodFn = <
+  TData = unknown,
+  TError = unknown,
+  ThrowOnError extends boolean = false,
+  TResponseStyle extends ResponseStyle = 'fields',
+>(
+  options: Omit<RequestOptions<TResponseStyle, ThrowOnError>, 'method'>,
+) => RequestResult<TData, TError, ThrowOnError, TResponseStyle>;
+
+type RequestFn = <
+  TData = unknown,
+  TError = unknown,
+  ThrowOnError extends boolean = false,
+  TResponseStyle extends ResponseStyle = 'fields',
+>(
+  options: Omit<RequestOptions<TResponseStyle, ThrowOnError>, 'method'> &
+    Pick<Required<RequestOptions<TResponseStyle, ThrowOnError>>, 'method'>,
+) => RequestResult<TData, TError, ThrowOnError, TResponseStyle>;
+
+type BuildUrlFn = <
+  TData extends {
+    body?: unknown;
+    path?: Record<string, unknown>;
+    query?: Record<string, unknown>;
+    url: string;
+  },
+>(
+  options: Pick<TData, 'url'> & Options<TData>,
+) => string;
+
+export type Client = CoreClient<RequestFn, Config, MethodFn, BuildUrlFn> & {
+  interceptors: Middleware<Request, Response, unknown, RequestOptions>;
+};
+
+/**
+ * The `createClientConfig()` function will be called on client initialization
+ * and the returned object will become the client's initial configuration.
+ *
+ * You may want to initialize your client this way instead of calling
+ * `setConfig()`. This is useful for example if you're using Next.js
+ * to ensure your client always has the correct values.
+ */
+export type CreateClientConfig<T extends ClientOptions = ClientOptions> = (
+  override?: Config<ClientOptions & T>,
+) => Config<Required<ClientOptions> & T>;
+
+export interface TDataShape {
+  body?: unknown;
+  headers?: unknown;
+  path?: unknown;
+  query?: unknown;
+  url: string;
+}
+
+type OmitKeys<T, K> = Pick<T, Exclude<keyof T, K>>;
+
+export type Options<
+  TData extends TDataShape = TDataShape,
+  ThrowOnError extends boolean = boolean,
+  TResponseStyle extends ResponseStyle = 'fields',
+> = OmitKeys<
+  RequestOptions<TResponseStyle, ThrowOnError>,
+  'body' | 'path' | 'query' | 'url'
+> &
+  Omit<TData, 'url'>;
+
+export type OptionsLegacyParser<
+  TData = unknown,
+  ThrowOnError extends boolean = boolean,
+  TResponseStyle extends ResponseStyle = 'fields',
+> = TData extends { body?: any }
+  ? TData extends { headers?: any }
+    ? OmitKeys<
+        RequestOptions<TResponseStyle, ThrowOnError>,
+        'body' | 'headers' | 'url'
+      > &
+        TData
+    : OmitKeys<RequestOptions<TResponseStyle, ThrowOnError>, 'body' | 'url'> &
+        TData &
+        Pick<RequestOptions<TResponseStyle, ThrowOnError>, 'headers'>
+  : TData extends { headers?: any }
+    ? OmitKeys<
+        RequestOptions<TResponseStyle, ThrowOnError>,
+        'headers' | 'url'
+      > &
+        TData &
+        Pick<RequestOptions<TResponseStyle, ThrowOnError>, 'body'>
+    : OmitKeys<RequestOptions<TResponseStyle, ThrowOnError>, 'url'> & TData;

examples/openapi-ts-tanstack-svelte-query/src/client/client/utils.ts

···
+import { getAuthToken } from '../core/auth';
+import type {
+  QuerySerializer,
+  QuerySerializerOptions,
+} from '../core/bodySerializer';
+import { jsonBodySerializer } from '../core/bodySerializer';
+import {
+  serializeArrayParam,
+  serializeObjectParam,
+  serializePrimitiveParam,
+} from '../core/pathSerializer';
+import type { Client, ClientOptions, Config, RequestOptions } from './types';
+
+interface PathSerializer {
+  path: Record<string, unknown>;
+  url: string;
+}
+
+const PATH_PARAM_RE = /\{[^{}]+\}/g;
+
+type ArrayStyle = 'form' | 'spaceDelimited' | 'pipeDelimited';
+type MatrixStyle = 'label' | 'matrix' | 'simple';
+type ArraySeparatorStyle = ArrayStyle | MatrixStyle;
+
+const defaultPathSerializer = ({ path, url: _url }: PathSerializer) => {
+  let url = _url;
+  const matches = _url.match(PATH_PARAM_RE);
+  if (matches) {
+    for (const match of matches) {
+      let explode = false;
+      let name = match.substring(1, match.length - 1);
+      let style: ArraySeparatorStyle = 'simple';
+
+      if (name.endsWith('*')) {
+        explode = true;
+        name = name.substring(0, name.length - 1);
+      }
+
+      if (name.startsWith('.')) {
+        name = name.substring(1);
+        style = 'label';
+      } else if (name.startsWith(';')) {
+        name = name.substring(1);
+        style = 'matrix';
+      }
+
+      const value = path[name];
+
+      if (value === undefined || value === null) {
+        continue;
+      }
+
+      if (Array.isArray(value)) {
+        url = url.replace(
+          match,
+          serializeArrayParam({ explode, name, style, value }),
+        );
+        continue;
+      }
+
+      if (typeof value === 'object') {
+        url = url.replace(
+          match,
+          serializeObjectParam({
+            explode,
+            name,
+            style,
+            value: value as Record<string, unknown>,
+            valueOnly: true,
+          }),
+        );
+        continue;
+      }
+
+      if (style === 'matrix') {
+        url = url.replace(
+          match,
+          `;${serializePrimitiveParam({
+            name,
+            value: value as string,
+          })}`,
+        );
+        continue;
+      }
+
+      const replaceValue = encodeURIComponent(
+        style === 'label' ? `.${value as string}` : (value as string),
+      );
+      url = url.replace(match, replaceValue);
+    }
+  }
+  return url;
+};
+
+export const createQuerySerializer = <T = unknown>({
+  allowReserved,
+  array,
+  object,
+}: QuerySerializerOptions = {}) => {
+  const querySerializer = (queryParams: T) => {
+    const search: string[] = [];
+    if (queryParams && typeof queryParams === 'object') {
+      for (const name in queryParams) {
+        const value = queryParams[name];
+
+        if (value === undefined || value === null) {
+          continue;
+        }
+
+        if (Array.isArray(value)) {
+          const serializedArray = serializeArrayParam({
+            allowReserved,
+            explode: true,
+            name,
+            style: 'form',
+            value,
+            ...array,
+          });
+          if (serializedArray) search.push(serializedArray);
+        } else if (typeof value === 'object') {
+          const serializedObject = serializeObjectParam({
+            allowReserved,
+            explode: true,
+            name,
+            style: 'deepObject',
+            value: value as Record<string, unknown>,
+            ...object,
+          });
+          if (serializedObject) search.push(serializedObject);
+        } else {
+          const serializedPrimitive = serializePrimitiveParam({
+            allowReserved,
+            name,
+            value: value as string,
+          });
+          if (serializedPrimitive) search.push(serializedPrimitive);
+        }
+      }
+    }
+    return search.join('&');
+  };
+  return querySerializer;
+};
+
+/**
+ * Infers parseAs value from provided Content-Type header.
+ */
+export const getParseAs = (
+  contentType: string | null,
+): Exclude<Config['parseAs'], 'auto'> => {
+  if (!contentType) {
+    // If no Content-Type header is provided, the best we can do is return the raw response body,
+    // which is effectively the same as the 'stream' option.
+    return 'stream';
+  }
+
+  const cleanContent = contentType.split(';')[0]?.trim();
+
+  if (!cleanContent) {
+    return;
+  }
+
+  if (
+    cleanContent.startsWith('application/json') ||
+    cleanContent.endsWith('+json')
+  ) {
+    return 'json';
+  }
+
+  if (cleanContent === 'multipart/form-data') {
+    return 'formData';
+  }
+
+  if (
+    ['application/', 'audio/', 'image/', 'video/'].some((type) =>
+      cleanContent.startsWith(type),
+    )
+  ) {
+    return 'blob';
+  }
+
+  if (cleanContent.startsWith('text/')) {
+    return 'text';
+  }
+};
+
+export const setAuthParams = async ({
+  security,
+  ...options
+}: Pick<Required<RequestOptions>, 'security'> &
+  Pick<RequestOptions, 'auth' | 'query'> & {
+    headers: Headers;
+  }) => {
+  for (const auth of security) {
+    const token = await getAuthToken(auth, options.auth);
+
+    if (!token) {
+      continue;
+    }
+
+    const name = auth.name ?? 'Authorization';
+
+    switch (auth.in) {
+      case 'query':
+        if (!options.query) {
+          options.query = {};
+        }
+        options.query[name] = token;
+        break;
+      case 'cookie':
+        options.headers.append('Cookie', `${name}=${token}`);
+        break;
+      case 'header':
+      default:
+        options.headers.set(name, token);
+        break;
+    }
+
+    return;
+  }
+};
+
+export const buildUrl: Client['buildUrl'] = (options) => {
+  const url = getUrl({
+    baseUrl: options.baseUrl as string,
+    path: options.path,
+    query: options.query,
+    querySerializer:
+      typeof options.querySerializer === 'function'
+        ? options.querySerializer
+        : createQuerySerializer(options.querySerializer),
+    url: options.url,
+  });
+  return url;
+};
+
+export const getUrl = ({
+  baseUrl,
+  path,
+  query,
+  querySerializer,
+  url: _url,
+}: {
+  baseUrl?: string;
+  path?: Record<string, unknown>;
+  query?: Record<string, unknown>;
+  querySerializer: QuerySerializer;
+  url: string;
+}) => {
+  const pathUrl = _url.startsWith('/') ? _url : `/${_url}`;
+  let url = (baseUrl ?? '') + pathUrl;
+  if (path) {
+    url = defaultPathSerializer({ path, url });
+  }
+  let search = query ? querySerializer(query) : '';
+  if (search.startsWith('?')) {
+    search = search.substring(1);
+  }
+  if (search) {
+    url += `?${search}`;
+  }
+  return url;
+};
+
+export const mergeConfigs = (a: Config, b: Config): Config => {
+  const config = { ...a, ...b };
+  if (config.baseUrl?.endsWith('/')) {
+    config.baseUrl = config.baseUrl.substring(0, config.baseUrl.length - 1);
+  }
+  config.headers = mergeHeaders(a.headers, b.headers);
+  return config;
+};
+
+export const mergeHeaders = (
+  ...headers: Array<Required<Config>['headers'] | undefined>
+): Headers => {
+  const mergedHeaders = new Headers();
+  for (const header of headers) {
+    if (!header || typeof header !== 'object') {
+      continue;
+    }
+
+    const iterator =
+      header instanceof Headers ? header.entries() : Object.entries(header);
+
+    for (const [key, value] of iterator) {
+      if (value === null) {
+        mergedHeaders.delete(key);
+      } else if (Array.isArray(value)) {
+        for (const v of value) {
+          mergedHeaders.append(key, v as string);
+        }
+      } else if (value !== undefined) {
+        // assume object headers are meant to be JSON stringified, i.e. their
+        // content value in OpenAPI specification is 'application/json'
+        mergedHeaders.set(
+          key,
+          typeof value === 'object' ? JSON.stringify(value) : (value as string),
+        );
+      }
+    }
+  }
+  return mergedHeaders;
+};
+
+type ErrInterceptor<Err, Res, Req, Options> = (
+  error: Err,
+  response: Res,
+  request: Req,
+  options: Options,
+) => Err | Promise<Err>;
+
+type ReqInterceptor<Req, Options> = (
+  request: Req,
+  options: Options,
+) => Req | Promise<Req>;
+
+type ResInterceptor<Res, Req, Options> = (
+  response: Res,
+  request: Req,
+  options: Options,
+) => Res | Promise<Res>;
+
+class Interceptors<Interceptor> {
+  _fns: (Interceptor | null)[];
+
+  constructor() {
+    this._fns = [];
+  }
+
+  clear() {
+    this._fns = [];
+  }
+
+  getInterceptorIndex(id: number | Interceptor): number {
+    if (typeof id === 'number') {
+      return this._fns[id] ? id : -1;
+    } else {
+      return this._fns.indexOf(id);
+    }
+  }
+  exists(id: number | Interceptor) {
+    const index = this.getInterceptorIndex(id);
+    return !!this._fns[index];
+  }
+
+  eject(id: number | Interceptor) {
+    const index = this.getInterceptorIndex(id);
+    if (this._fns[index]) {
+      this._fns[index] = null;
+    }
+  }
+
+  update(id: number | Interceptor, fn: Interceptor) {
+    const index = this.getInterceptorIndex(id);
+    if (this._fns[index]) {
+      this._fns[index] = fn;
+      return id;
+    } else {
+      return false;
+    }
+  }
+
+  use(fn: Interceptor) {
+    this._fns = [...this._fns, fn];
+    return this._fns.length - 1;
+  }
+}
+
+// `createInterceptors()` response, meant for external use as it does not
+// expose internals
+export interface Middleware<Req, Res, Err, Options> {
+  error: Pick<
+    Interceptors<ErrInterceptor<Err, Res, Req, Options>>,
+    'eject' | 'use'
+  >;
+  request: Pick<Interceptors<ReqInterceptor<Req, Options>>, 'eject' | 'use'>;
+  response: Pick<
+    Interceptors<ResInterceptor<Res, Req, Options>>,
+    'eject' | 'use'
+  >;
+}
+
+// do not add `Middleware` as return type so we can use _fns internally
+export const createInterceptors = <Req, Res, Err, Options>() => ({
+  error: new Interceptors<ErrInterceptor<Err, Res, Req, Options>>(),
+  request: new Interceptors<ReqInterceptor<Req, Options>>(),
+  response: new Interceptors<ResInterceptor<Res, Req, Options>>(),
+});
+
+const defaultQuerySerializer = createQuerySerializer({
+  allowReserved: false,
+  array: {
+    explode: true,
+    style: 'form',
+  },
+  object: {
+    explode: true,
+    style: 'deepObject',
+  },
+});
+
+const defaultHeaders = {
+  'Content-Type': 'application/json',
+};
+
+export const createConfig = <T extends ClientOptions = ClientOptions>(
+  override: Config<Omit<ClientOptions, keyof T> & T> = {},
+): Config<Omit<ClientOptions, keyof T> & T> => ({
+  ...jsonBodySerializer,
+  headers: defaultHeaders,
+  parseAs: 'auto',
+  querySerializer: defaultQuerySerializer,
+  ...override,
+});

examples/openapi-ts-tanstack-svelte-query/src/client/core/auth.ts

···
+export type AuthToken = string | undefined;
+
+export interface Auth {
+  /**
+   * Which part of the request do we use to send the auth?
+   *
+   * @default 'header'
+   */
+  in?: 'header' | 'query' | 'cookie';
+  /**
+   * Header or query parameter name.
+   *
+   * @default 'Authorization'
+   */
+  name?: string;
+  scheme?: 'basic' | 'bearer';
+  type: 'apiKey' | 'http';
+}
+
+export const getAuthToken = async (
+  auth: Auth,
+  callback: ((auth: Auth) => Promise<AuthToken> | AuthToken) | AuthToken,
+): Promise<string | undefined> => {
+  const token =
+    typeof callback === 'function' ? await callback(auth) : callback;
+
+  if (!token) {
+    return;
+  }
+
+  if (auth.scheme === 'bearer') {
+    return `Bearer ${token}`;
+  }
+
+  if (auth.scheme === 'basic') {
+    return `Basic ${btoa(token)}`;
+  }
+
+  return token;
+};

examples/openapi-ts-tanstack-svelte-query/src/client/core/bodySerializer.ts

···
+import type {
+  ArrayStyle,
+  ObjectStyle,
+  SerializerOptions,
+} from './pathSerializer';
+
+export type QuerySerializer = (query: Record<string, unknown>) => string;
+
+export type BodySerializer = (body: any) => any;
+
+export interface QuerySerializerOptions {
+  allowReserved?: boolean;
+  array?: SerializerOptions<ArrayStyle>;
+  object?: SerializerOptions<ObjectStyle>;
+}
+
+const serializeFormDataPair = (data: FormData, key: string, value: unknown) => {
+  if (typeof value === 'string' || value instanceof Blob) {
+    data.append(key, value);
+  } else {
+    data.append(key, JSON.stringify(value));
+  }
+};
+
+const serializeUrlSearchParamsPair = (
+  data: URLSearchParams,
+  key: string,
+  value: unknown,
+) => {
+  if (typeof value === 'string') {
+    data.append(key, value);
+  } else {
+    data.append(key, JSON.stringify(value));
+  }
+};
+
+export const formDataBodySerializer = {
+  bodySerializer: <T extends Record<string, any> | Array<Record<string, any>>>(
+    body: T,
+  ) => {
+    const data = new FormData();
+
+    Object.entries(body).forEach(([key, value]) => {
+      if (value === undefined || value === null) {
+        return;
+      }
+      if (Array.isArray(value)) {
+        value.forEach((v) => serializeFormDataPair(data, key, v));
+      } else {
+        serializeFormDataPair(data, key, value);
+      }
+    });
+
+    return data;
+  },
+};
+
+export const jsonBodySerializer = {
+  bodySerializer: <T>(body: T) =>
+    JSON.stringify(body, (key, value) =>
+      typeof value === 'bigint' ? value.toString() : value,
+    ),
+};
+
+export const urlSearchParamsBodySerializer = {
+  bodySerializer: <T extends Record<string, any> | Array<Record<string, any>>>(
+    body: T,
+  ) => {
+    const data = new URLSearchParams();
+
+    Object.entries(body).forEach(([key, value]) => {
+      if (value === undefined || value === null) {
+        return;
+      }
+      if (Array.isArray(value)) {
+        value.forEach((v) => serializeUrlSearchParamsPair(data, key, v));
+      } else {
+        serializeUrlSearchParamsPair(data, key, value);
+      }
+    });
+
+    return data.toString();
+  },
+};

examples/openapi-ts-tanstack-svelte-query/src/client/core/params.ts

···
+type Slot = 'body' | 'headers' | 'path' | 'query';
+
+export type Field =
+  | {
+      in: Exclude<Slot, 'body'>;
+      key: string;
+      map?: string;
+    }
+  | {
+      in: Extract<Slot, 'body'>;
+      key?: string;
+      map?: string;
+    };
+
+export interface Fields {
+  allowExtra?: Partial<Record<Slot, boolean>>;
+  args?: ReadonlyArray<Field>;
+}
+
+export type FieldsConfig = ReadonlyArray<Field | Fields>;
+
+const extraPrefixesMap: Record<string, Slot> = {
+  $body_: 'body',
+  $headers_: 'headers',
+  $path_: 'path',
+  $query_: 'query',
+};
+const extraPrefixes = Object.entries(extraPrefixesMap);
+
+type KeyMap = Map<
+  string,
+  {
+    in: Slot;
+    map?: string;
+  }
+>;
+
+const buildKeyMap = (fields: FieldsConfig, map?: KeyMap): KeyMap => {
+  if (!map) {
+    map = new Map();
+  }
+
+  for (const config of fields) {
+    if ('in' in config) {
+      if (config.key) {
+        map.set(config.key, {
+          in: config.in,
+          map: config.map,
+        });
+      }
+    } else if (config.args) {
+      buildKeyMap(config.args, map);
+    }
+  }
+
+  return map;
+};
+
+interface Params {
+  body: unknown;
+  headers: Record<string, unknown>;
+  path: Record<string, unknown>;
+  query: Record<string, unknown>;
+}
+
+const stripEmptySlots = (params: Params) => {
+  for (const [slot, value] of Object.entries(params)) {
+    if (value && typeof value === 'object' && !Object.keys(value).length) {
+      delete params[slot as Slot];
+    }
+  }
+};
+
+export const buildClientParams = (
+  args: ReadonlyArray<unknown>,
+  fields: FieldsConfig,
+) => {
+  const params: Params = {
+    body: {},
+    headers: {},
+    path: {},
+    query: {},
+  };
+
+  const map = buildKeyMap(fields);
+
+  let config: FieldsConfig[number] | undefined;
+
+  for (const [index, arg] of args.entries()) {
+    if (fields[index]) {
+      config = fields[index];
+    }
+
+    if (!config) {
+      continue;
+    }
+
+    if ('in' in config) {
+      if (config.key) {
+        const field = map.get(config.key)!;
+        const name = field.map || config.key;
+        (params[field.in] as Record<string, unknown>)[name] = arg;
+      } else {
+        params.body = arg;
+      }
+    } else {
+      for (const [key, value] of Object.entries(arg ?? {})) {
+        const field = map.get(key);
+
+        if (field) {
+          const name = field.map || key;
+          (params[field.in] as Record<string, unknown>)[name] = value;
+        } else {
+          const extra = extraPrefixes.find(([prefix]) =>
+            key.startsWith(prefix),
+          );
+
+          if (extra) {
+            const [prefix, slot] = extra;
+            (params[slot] as Record<string, unknown>)[
+              key.slice(prefix.length)
+            ] = value;
+          } else {
+            for (const [slot, allowed] of Object.entries(
+              config.allowExtra ?? {},
+            )) {
+              if (allowed) {
+                (params[slot as Slot] as Record<string, unknown>)[key] = value;
+                break;
+              }
+            }
+          }
+        }
+      }
+    }
+  }
+
+  stripEmptySlots(params);
+
+  return params;
+};

examples/openapi-ts-tanstack-svelte-query/src/client/core/pathSerializer.ts

···
+interface SerializeOptions<T>
+  extends SerializePrimitiveOptions,
+    SerializerOptions<T> {}
+
+interface SerializePrimitiveOptions {
+  allowReserved?: boolean;
+  name: string;
+}
+
+export interface SerializerOptions<T> {
+  /**
+   * @default true
+   */
+  explode: boolean;
+  style: T;
+}
+
+export type ArrayStyle = 'form' | 'spaceDelimited' | 'pipeDelimited';
+export type ArraySeparatorStyle = ArrayStyle | MatrixStyle;
+type MatrixStyle = 'label' | 'matrix' | 'simple';
+export type ObjectStyle = 'form' | 'deepObject';
+type ObjectSeparatorStyle = ObjectStyle | MatrixStyle;
+
+interface SerializePrimitiveParam extends SerializePrimitiveOptions {
+  value: string;
+}
+
+export const separatorArrayExplode = (style: ArraySeparatorStyle) => {
+  switch (style) {
+    case 'label':
+      return '.';
+    case 'matrix':
+      return ';';
+    case 'simple':
+      return ',';
+    default:
+      return '&';
+  }
+};
+
+export const separatorArrayNoExplode = (style: ArraySeparatorStyle) => {
+  switch (style) {
+    case 'form':
+      return ',';
+    case 'pipeDelimited':
+      return '|';
+    case 'spaceDelimited':
+      return '%20';
+    default:
+      return ',';
+  }
+};
+
+export const separatorObjectExplode = (style: ObjectSeparatorStyle) => {
+  switch (style) {
+    case 'label':
+      return '.';
+    case 'matrix':
+      return ';';
+    case 'simple':
+      return ',';
+    default:
+      return '&';
+  }
+};
+
+export const serializeArrayParam = ({
+  allowReserved,
+  explode,
+  name,
+  style,
+  value,
+}: SerializeOptions<ArraySeparatorStyle> & {
+  value: unknown[];
+}) => {
+  if (!explode) {
+    const joinedValues = (
+      allowReserved ? value : value.map((v) => encodeURIComponent(v as string))
+    ).join(separatorArrayNoExplode(style));
+    switch (style) {
+      case 'label':
+        return `.${joinedValues}`;
+      case 'matrix':
+        return `;${name}=${joinedValues}`;
+      case 'simple':
+        return joinedValues;
+      default:
+        return `${name}=${joinedValues}`;
+    }
+  }
+
+  const separator = separatorArrayExplode(style);
+  const joinedValues = value
+    .map((v) => {
+      if (style === 'label' || style === 'simple') {
+        return allowReserved ? v : encodeURIComponent(v as string);
+      }
+
+      return serializePrimitiveParam({
+        allowReserved,
+        name,
+        value: v as string,
+      });
+    })
+    .join(separator);
+  return style === 'label' || style === 'matrix'
+    ? separator + joinedValues
+    : joinedValues;
+};
+
+export const serializePrimitiveParam = ({
+  allowReserved,
+  name,
+  value,
+}: SerializePrimitiveParam) => {
+  if (value === undefined || value === null) {
+    return '';
+  }
+
+  if (typeof value === 'object') {
+    throw new Error(
+      'Deeply-nested arrays/objects aren’t supported. Provide your own `querySerializer()` to handle these.',
+    );
+  }
+
+  return `${name}=${allowReserved ? value : encodeURIComponent(value)}`;
+};
+
+export const serializeObjectParam = ({
+  allowReserved,
+  explode,
+  name,
+  style,
+  value,
+  valueOnly,
+}: SerializeOptions<ObjectSeparatorStyle> & {
+  value: Record<string, unknown> | Date;
+  valueOnly?: boolean;
+}) => {
+  if (value instanceof Date) {
+    return valueOnly ? value.toISOString() : `${name}=${value.toISOString()}`;
+  }
+
+  if (style !== 'deepObject' && !explode) {
+    let values: string[] = [];
+    Object.entries(value).forEach(([key, v]) => {
+      values = [
+        ...values,
+        key,
+        allowReserved ? (v as string) : encodeURIComponent(v as string),
+      ];
+    });
+    const joinedValues = values.join(',');
+    switch (style) {
+      case 'form':
+        return `${name}=${joinedValues}`;
+      case 'label':
+        return `.${joinedValues}`;
+      case 'matrix':
+        return `;${name}=${joinedValues}`;
+      default:
+        return joinedValues;
+    }
+  }
+
+  const separator = separatorObjectExplode(style);
+  const joinedValues = Object.entries(value)
+    .map(([key, v]) =>
+      serializePrimitiveParam({
+        allowReserved,
+        name: style === 'deepObject' ? `${name}[${key}]` : key,
+        value: v as string,
+      }),
+    )
+    .join(separator);
+  return style === 'label' || style === 'matrix'
+    ? separator + joinedValues
+    : joinedValues;
+};

examples/openapi-ts-tanstack-svelte-query/src/client/core/types.ts

···
+import type { Auth, AuthToken } from './auth';
+import type {
+  BodySerializer,
+  QuerySerializer,
+  QuerySerializerOptions,
+} from './bodySerializer';
+
+export interface Client<
+  RequestFn = never,
+  Config = unknown,
+  MethodFn = never,
+  BuildUrlFn = never,
+> {
+  /**
+   * Returns the final request URL.
+   */
+  buildUrl: BuildUrlFn;
+  connect: MethodFn;
+  delete: MethodFn;
+  get: MethodFn;
+  getConfig: () => Config;
+  head: MethodFn;
+  options: MethodFn;
+  patch: MethodFn;
+  post: MethodFn;
+  put: MethodFn;
+  request: RequestFn;
+  setConfig: (config: Config) => Config;
+  trace: MethodFn;
+}
+
+export interface Config {
+  /**
+   * Auth token or a function returning auth token. The resolved value will be
+   * added to the request payload as defined by its `security` array.
+   */
+  auth?: ((auth: Auth) => Promise<AuthToken> | AuthToken) | AuthToken;
+  /**
+   * A function for serializing request body parameter. By default,
+   * {@link JSON.stringify()} will be used.
+   */
+  bodySerializer?: BodySerializer | null;
+  /**
+   * An object containing any HTTP headers that you want to pre-populate your
+   * `Headers` object with.
+   *
+   * {@link https://developer.mozilla.org/docs/Web/API/Headers/Headers#init See more}
+   */
+  headers?:
+    | RequestInit['headers']
+    | Record<
+        string,
+        | string
+        | number
+        | boolean
+        | (string | number | boolean)[]
+        | null
+        | undefined
+        | unknown
+      >;
+  /**
+   * The request method.
+   *
+   * {@link https://developer.mozilla.org/docs/Web/API/fetch#method See more}
+   */
+  method?:
+    | 'CONNECT'
+    | 'DELETE'
+    | 'GET'
+    | 'HEAD'
+    | 'OPTIONS'
+    | 'PATCH'
+    | 'POST'
+    | 'PUT'
+    | 'TRACE';
+  /**
+   * A function for serializing request query parameters. By default, arrays
+   * will be exploded in form style, objects will be exploded in deepObject
+   * style, and reserved characters are percent-encoded.
+   *
+   * This method will have no effect if the native `paramsSerializer()` Axios
+   * API function is used.
+   *
+   * {@link https://swagger.io/docs/specification/serialization/#query View examples}
+   */
+  querySerializer?: QuerySerializer | QuerySerializerOptions;
+  /**
+   * A function transforming response data before it's returned. This is useful
+   * for post-processing data, e.g. converting ISO strings into Date objects.
+   */
+  responseTransformer?: (data: unknown) => Promise<unknown>;
+  /**
+   * A function validating response data. This is useful if you want to ensure
+   * the response conforms to the desired shape, so it can be safely passed to
+   * the transformers and returned to the user.
+   */
+  responseValidator?: (data: unknown) => Promise<unknown>;
+}

examples/openapi-ts-tanstack-svelte-query/src/client/sdk.gen.ts

···
 // This file is auto-generated by @hey-api/openapi-ts
 
-import type {
-  Client,
-  Options as ClientOptions,
-  TDataShape,
-} from '@hey-api/client-fetch';
-
+import type { Client, Options as ClientOptions, TDataShape } from './client';
 import { client as _heyApiClient } from './client.gen';
 import type {
   AddPetData,
···
     ...options,
     headers: {
       'Content-Type': 'application/json',
-      ...options?.headers,
+      ...options.headers,
     },
   });
 
···
     ...options,
     headers: {
       'Content-Type': 'application/json',
-      ...options?.headers,
+      ...options.headers,
     },
   });
 
···
     ...options,
     headers: {
       'Content-Type': 'application/octet-stream',
-      ...options?.headers,
+      ...options.headers,
     },
   });
 
···
     ...options,
     headers: {
       'Content-Type': 'application/json',
-      ...options?.headers,
+      ...options.headers,
     },
   });

examples/openapi-ts-tanstack-vue-query/package.json

···
     "typecheck": "vue-tsc --build --force"
   },
   "dependencies": {
-    "@hey-api/client-fetch": "workspace:*",
     "@tanstack/vue-query": "5.73.3",
     "@tanstack/vue-query-devtools": "5.73.3",
     "pinia": "2.3.0",

examples/openapi-ts-tanstack-vue-query/src/client/client.gen.ts

···
   type Config,
   createClient,
   createConfig
-} from '@hey-api/client-fetch'
-
+} from './client'
 import type { ClientOptions } from './types.gen'
 
 /**

examples/openapi-ts-tanstack-vue-query/src/client/client/client.ts

···
+import type { Client, Config, RequestOptions } from './types'
+import {
+  buildUrl,
+  createConfig,
+  createInterceptors,
+  getParseAs,
+  mergeConfigs,
+  mergeHeaders,
+  setAuthParams
+} from './utils'
+
+type ReqInit = Omit<RequestInit, 'body' | 'headers'> & {
+  body?: any
+  headers: ReturnType<typeof mergeHeaders>
+}
+
+export const createClient = (config: Config = {}): Client => {
+  let _config = mergeConfigs(createConfig(), config)
+
+  const getConfig = (): Config => ({ ..._config })
+
+  const setConfig = (config: Config): Config => {
+    _config = mergeConfigs(_config, config)
+    return getConfig()
+  }
+
+  const interceptors = createInterceptors<Request, Response, unknown, RequestOptions>()
+
+  const request: Client['request'] = async (options) => {
+    const opts = {
+      ..._config,
+      ...options,
+      fetch: options.fetch ?? _config.fetch ?? globalThis.fetch,
+      headers: mergeHeaders(_config.headers, options.headers)
+    }
+
+    if (opts.security) {
+      await setAuthParams({
+        ...opts,
+        security: opts.security
+      })
+    }
+
+    if (opts.body && opts.bodySerializer) {
+      opts.body = opts.bodySerializer(opts.body)
+    }
+
+    // remove Content-Type header if body is empty to avoid sending invalid requests
+    if (opts.body === undefined || opts.body === '') {
+      opts.headers.delete('Content-Type')
+    }
+
+    const url = buildUrl(opts)
+    const requestInit: ReqInit = {
+      redirect: 'follow',
+      ...opts
+    }
+
+    let request = new Request(url, requestInit)
+
+    for (const fn of interceptors.request._fns) {
+      if (fn) {
+        request = await fn(request, opts)
+      }
+    }
+
+    // fetch must be assigned here, otherwise it would throw the error:
+    // TypeError: Failed to execute 'fetch' on 'Window': Illegal invocation
+    const _fetch = opts.fetch!
+    let response = await _fetch(request)
+
+    for (const fn of interceptors.response._fns) {
+      if (fn) {
+        response = await fn(response, request, opts)
+      }
+    }
+
+    const result = {
+      request,
+      response
+    }
+
+    if (response.ok) {
+      if (response.status === 204 || response.headers.get('Content-Length') === '0') {
+        return opts.responseStyle === 'data'
+          ? {}
+          : {
+              data: {},
+              ...result
+            }
+      }
+
+      const parseAs =
+        (opts.parseAs === 'auto'
+          ? getParseAs(response.headers.get('Content-Type'))
+          : opts.parseAs) ?? 'json'
+
+      if (parseAs === 'stream') {
+        return opts.responseStyle === 'data'
+          ? response.body
+          : {
+              data: response.body,
+              ...result
+            }
+      }
+
+      let data = await response[parseAs]()
+      if (parseAs === 'json') {
+        if (opts.responseValidator) {
+          await opts.responseValidator(data)
+        }
+
+        if (opts.responseTransformer) {
+          data = await opts.responseTransformer(data)
+        }
+      }
+
+      return opts.responseStyle === 'data'
+        ? data
+        : {
+            data,
+            ...result
+          }
+    }
+
+    let error = await response.text()
+
+    try {
+      error = JSON.parse(error)
+    } catch {
+      // noop
+    }
+
+    let finalError = error
+
+    for (const fn of interceptors.error._fns) {
+      if (fn) {
+        finalError = (await fn(error, response, request, opts)) as string
+      }
+    }
+
+    finalError = finalError || ({} as string)
+
+    if (opts.throwOnError) {
+      throw finalError
+    }
+
+    // TODO: we probably want to return error and improve types
+    return opts.responseStyle === 'data'
+      ? undefined
+      : {
+          error: finalError,
+          ...result
+        }
+  }
+
+  return {
+    buildUrl,
+    connect: (options) => request({ ...options, method: 'CONNECT' }),
+    delete: (options) => request({ ...options, method: 'DELETE' }),
+    get: (options) => request({ ...options, method: 'GET' }),
+    getConfig,
+    head: (options) => request({ ...options, method: 'HEAD' }),
+    interceptors,
+    options: (options) => request({ ...options, method: 'OPTIONS' }),
+    patch: (options) => request({ ...options, method: 'PATCH' }),
+    post: (options) => request({ ...options, method: 'POST' }),
+    put: (options) => request({ ...options, method: 'PUT' }),
+    request,
+    setConfig,
+    trace: (options) => request({ ...options, method: 'TRACE' })
+  }
+}

examples/openapi-ts-tanstack-vue-query/src/client/client/index.ts

···
+export type { Auth } from '../core/auth'
+export type { QuerySerializerOptions } from '../core/bodySerializer'
+export {
+  formDataBodySerializer,
+  jsonBodySerializer,
+  urlSearchParamsBodySerializer
+} from '../core/bodySerializer'
+export { buildClientParams } from '../core/params'
+export { createClient } from './client'
+export type {
+  Client,
+  ClientOptions,
+  Config,
+  CreateClientConfig,
+  Options,
+  OptionsLegacyParser,
+  RequestOptions,
+  RequestResult,
+  ResponseStyle,
+  TDataShape
+} from './types'
+export { createConfig, mergeHeaders } from './utils'

examples/openapi-ts-tanstack-vue-query/src/client/client/types.ts

···
+import type { Auth } from '../core/auth'
+import type { Client as CoreClient, Config as CoreConfig } from '../core/types'
+import type { Middleware } from './utils'
+
+export type ResponseStyle = 'data' | 'fields'
+
+export interface Config<T extends ClientOptions = ClientOptions>
+  extends Omit<RequestInit, 'body' | 'headers' | 'method'>,
+    CoreConfig {
+  /**
+   * Base URL for all requests made by this client.
+   */
+  baseUrl?: T['baseUrl']
+  /**
+   * Fetch API implementation. You can use this option to provide a custom
+   * fetch instance.
+   *
+   * @default globalThis.fetch
+   */
+  fetch?: (request: Request) => ReturnType<typeof fetch>
+  /**
+   * Please don't use the Fetch client for Next.js applications. The `next`
+   * options won't have any effect.
+   *
+   * Install {@link https://www.npmjs.com/package/@hey-api/client-next `@hey-api/client-next`} instead.
+   */
+  next?: never
+  /**
+   * Return the response data parsed in a specified format. By default, `auto`
+   * will infer the appropriate method from the `Content-Type` response header.
+   * You can override this behavior with any of the {@link Body} methods.
+   * Select `stream` if you don't want to parse response data at all.
+   *
+   * @default 'auto'
+   */
+  parseAs?: Exclude<keyof Body, 'body' | 'bodyUsed'> | 'auto' | 'stream'
+  /**
+   * Should we return only data or multiple fields (data, error, response, etc.)?
+   *
+   * @default 'fields'
+   */
+  responseStyle?: ResponseStyle
+  /**
+   * Throw an error instead of returning it in the response?
+   *
+   * @default false
+   */
+  throwOnError?: T['throwOnError']
+}
+
+export interface RequestOptions<
+  TResponseStyle extends ResponseStyle = 'fields',
+  ThrowOnError extends boolean = boolean,
+  Url extends string = string
+> extends Config<{
+    responseStyle: TResponseStyle
+    throwOnError: ThrowOnError
+  }> {
+  /**
+   * Any body that you want to add to your request.
+   *
+   * {@link https://developer.mozilla.org/docs/Web/API/fetch#body}
+   */
+  body?: unknown
+  path?: Record<string, unknown>
+  query?: Record<string, unknown>
+  /**
+   * Security mechanism(s) to use for the request.
+   */
+  security?: ReadonlyArray<Auth>
+  url: Url
+}
+
+export type RequestResult<
+  TData = unknown,
+  TError = unknown,
+  ThrowOnError extends boolean = boolean,
+  TResponseStyle extends ResponseStyle = 'fields'
+> = ThrowOnError extends true
+  ? Promise<
+      TResponseStyle extends 'data'
+        ? TData extends Record<string, unknown>
+          ? TData[keyof TData]
+          : TData
+        : {
+            data: TData extends Record<string, unknown> ? TData[keyof TData] : TData
+            request: Request
+            response: Response
+          }
+    >
+  : Promise<
+      TResponseStyle extends 'data'
+        ? (TData extends Record<string, unknown> ? TData[keyof TData] : TData) | undefined
+        : (
+            | {
+                data: TData extends Record<string, unknown> ? TData[keyof TData] : TData
+                error: undefined
+              }
+            | {
+                data: undefined
+                error: TError extends Record<string, unknown> ? TError[keyof TError] : TError
+              }
+          ) & {
+            request: Request
+            response: Response
+          }
+    >
+
+export interface ClientOptions {
+  baseUrl?: string
+  responseStyle?: ResponseStyle
+  throwOnError?: boolean
+}
+
+type MethodFn = <
+  TData = unknown,
+  TError = unknown,
+  ThrowOnError extends boolean = false,
+  TResponseStyle extends ResponseStyle = 'fields'
+>(
+  options: Omit<RequestOptions<TResponseStyle, ThrowOnError>, 'method'>
+) => RequestResult<TData, TError, ThrowOnError, TResponseStyle>
+
+type RequestFn = <
+  TData = unknown,
+  TError = unknown,
+  ThrowOnError extends boolean = false,
+  TResponseStyle extends ResponseStyle = 'fields'
+>(
+  options: Omit<RequestOptions<TResponseStyle, ThrowOnError>, 'method'> &
+    Pick<Required<RequestOptions<TResponseStyle, ThrowOnError>>, 'method'>
+) => RequestResult<TData, TError, ThrowOnError, TResponseStyle>
+
+type BuildUrlFn = <
+  TData extends {
+    body?: unknown
+    path?: Record<string, unknown>
+    query?: Record<string, unknown>
+    url: string
+  }
+>(
+  options: Pick<TData, 'url'> & Options<TData>
+) => string
+
+export type Client = CoreClient<RequestFn, Config, MethodFn, BuildUrlFn> & {
+  interceptors: Middleware<Request, Response, unknown, RequestOptions>
+}
+
+/**
+ * The `createClientConfig()` function will be called on client initialization
+ * and the returned object will become the client's initial configuration.
+ *
+ * You may want to initialize your client this way instead of calling
+ * `setConfig()`. This is useful for example if you're using Next.js
+ * to ensure your client always has the correct values.
+ */
+export type CreateClientConfig<T extends ClientOptions = ClientOptions> = (
+  override?: Config<ClientOptions & T>
+) => Config<Required<ClientOptions> & T>
+
+export interface TDataShape {
+  body?: unknown
+  headers?: unknown
+  path?: unknown
+  query?: unknown
+  url: string
+}
+
+type OmitKeys<T, K> = Pick<T, Exclude<keyof T, K>>
+
+export type Options<
+  TData extends TDataShape = TDataShape,
+  ThrowOnError extends boolean = boolean,
+  TResponseStyle extends ResponseStyle = 'fields'
+> = OmitKeys<RequestOptions<TResponseStyle, ThrowOnError>, 'body' | 'path' | 'query' | 'url'> &
+  Omit<TData, 'url'>
+
+export type OptionsLegacyParser<
+  TData = unknown,
+  ThrowOnError extends boolean = boolean,
+  TResponseStyle extends ResponseStyle = 'fields'
+> = TData extends { body?: any }
+  ? TData extends { headers?: any }
+    ? OmitKeys<RequestOptions<TResponseStyle, ThrowOnError>, 'body' | 'headers' | 'url'> & TData
+    : OmitKeys<RequestOptions<TResponseStyle, ThrowOnError>, 'body' | 'url'> &
+        TData &
+        Pick<RequestOptions<TResponseStyle, ThrowOnError>, 'headers'>
+  : TData extends { headers?: any }
+    ? OmitKeys<RequestOptions<TResponseStyle, ThrowOnError>, 'headers' | 'url'> &
+        TData &
+        Pick<RequestOptions<TResponseStyle, ThrowOnError>, 'body'>
+    : OmitKeys<RequestOptions<TResponseStyle, ThrowOnError>, 'url'> & TData

examples/openapi-ts-tanstack-vue-query/src/client/client/utils.ts

···
+import { getAuthToken } from '../core/auth'
+import type { QuerySerializer, QuerySerializerOptions } from '../core/bodySerializer'
+import { jsonBodySerializer } from '../core/bodySerializer'
+import {
+  serializeArrayParam,
+  serializeObjectParam,
+  serializePrimitiveParam
+} from '../core/pathSerializer'
+import type { Client, ClientOptions, Config, RequestOptions } from './types'
+
+interface PathSerializer {
+  path: Record<string, unknown>
+  url: string
+}
+
+const PATH_PARAM_RE = /\{[^{}]+\}/g
+
+type ArrayStyle = 'form' | 'spaceDelimited' | 'pipeDelimited'
+type MatrixStyle = 'label' | 'matrix' | 'simple'
+type ArraySeparatorStyle = ArrayStyle | MatrixStyle
+
+const defaultPathSerializer = ({ path, url: _url }: PathSerializer) => {
+  let url = _url
+  const matches = _url.match(PATH_PARAM_RE)
+  if (matches) {
+    for (const match of matches) {
+      let explode = false
+      let name = match.substring(1, match.length - 1)
+      let style: ArraySeparatorStyle = 'simple'
+
+      if (name.endsWith('*')) {
+        explode = true
+        name = name.substring(0, name.length - 1)
+      }
+
+      if (name.startsWith('.')) {
+        name = name.substring(1)
+        style = 'label'
+      } else if (name.startsWith(';')) {
+        name = name.substring(1)
+        style = 'matrix'
+      }
+
+      const value = path[name]
+
+      if (value === undefined || value === null) {
+        continue
+      }
+
+      if (Array.isArray(value)) {
+        url = url.replace(match, serializeArrayParam({ explode, name, style, value }))
+        continue
+      }
+
+      if (typeof value === 'object') {
+        url = url.replace(
+          match,
+          serializeObjectParam({
+            explode,
+            name,
+            style,
+            value: value as Record<string, unknown>,
+            valueOnly: true
+          })
+        )
+        continue
+      }
+
+      if (style === 'matrix') {
+        url = url.replace(
+          match,
+          `;${serializePrimitiveParam({
+            name,
+            value: value as string
+          })}`
+        )
+        continue
+      }
+
+      const replaceValue = encodeURIComponent(
+        style === 'label' ? `.${value as string}` : (value as string)
+      )
+      url = url.replace(match, replaceValue)
+    }
+  }
+  return url
+}
+
+export const createQuerySerializer = <T = unknown>({
+  allowReserved,
+  array,
+  object
+}: QuerySerializerOptions = {}) => {
+  const querySerializer = (queryParams: T) => {
+    const search: string[] = []
+    if (queryParams && typeof queryParams === 'object') {
+      for (const name in queryParams) {
+        const value = queryParams[name]
+
+        if (value === undefined || value === null) {
+          continue
+        }
+
+        if (Array.isArray(value)) {
+          const serializedArray = serializeArrayParam({
+            allowReserved,
+            explode: true,
+            name,
+            style: 'form',
+            value,
+            ...array
+          })
+          if (serializedArray) search.push(serializedArray)
+        } else if (typeof value === 'object') {
+          const serializedObject = serializeObjectParam({
+            allowReserved,
+            explode: true,
+            name,
+            style: 'deepObject',
+            value: value as Record<string, unknown>,
+            ...object
+          })
+          if (serializedObject) search.push(serializedObject)
+        } else {
+          const serializedPrimitive = serializePrimitiveParam({
+            allowReserved,
+            name,
+            value: value as string
+          })
+          if (serializedPrimitive) search.push(serializedPrimitive)
+        }
+      }
+    }
+    return search.join('&')
+  }
+  return querySerializer
+}
+
+/**
+ * Infers parseAs value from provided Content-Type header.
+ */
+export const getParseAs = (contentType: string | null): Exclude<Config['parseAs'], 'auto'> => {
+  if (!contentType) {
+    // If no Content-Type header is provided, the best we can do is return the raw response body,
+    // which is effectively the same as the 'stream' option.
+    return 'stream'
+  }
+
+  const cleanContent = contentType.split(';')[0]?.trim()
+
+  if (!cleanContent) {
+    return
+  }
+
+  if (cleanContent.startsWith('application/json') || cleanContent.endsWith('+json')) {
+    return 'json'
+  }
+
+  if (cleanContent === 'multipart/form-data') {
+    return 'formData'
+  }
+
+  if (
+    ['application/', 'audio/', 'image/', 'video/'].some((type) => cleanContent.startsWith(type))
+  ) {
+    return 'blob'
+  }
+
+  if (cleanContent.startsWith('text/')) {
+    return 'text'
+  }
+}
+
+export const setAuthParams = async ({
+  security,
+  ...options
+}: Pick<Required<RequestOptions>, 'security'> &
+  Pick<RequestOptions, 'auth' | 'query'> & {
+    headers: Headers
+  }) => {
+  for (const auth of security) {
+    const token = await getAuthToken(auth, options.auth)
+
+    if (!token) {
+      continue
+    }
+
+    const name = auth.name ?? 'Authorization'
+
+    switch (auth.in) {
+      case 'query':
+        if (!options.query) {
+          options.query = {}
+        }
+        options.query[name] = token
+        break
+      case 'cookie':
+        options.headers.append('Cookie', `${name}=${token}`)
+        break
+      case 'header':
+      default:
+        options.headers.set(name, token)
+        break
+    }
+
+    return
+  }
+}
+
+export const buildUrl: Client['buildUrl'] = (options) => {
+  const url = getUrl({
+    baseUrl: options.baseUrl as string,
+    path: options.path,
+    query: options.query,
+    querySerializer:
+      typeof options.querySerializer === 'function'
+        ? options.querySerializer
+        : createQuerySerializer(options.querySerializer),
+    url: options.url
+  })
+  return url
+}
+
+export const getUrl = ({
+  baseUrl,
+  path,
+  query,
+  querySerializer,
+  url: _url
+}: {
+  baseUrl?: string
+  path?: Record<string, unknown>
+  query?: Record<string, unknown>
+  querySerializer: QuerySerializer
+  url: string
+}) => {
+  const pathUrl = _url.startsWith('/') ? _url : `/${_url}`
+  let url = (baseUrl ?? '') + pathUrl
+  if (path) {
+    url = defaultPathSerializer({ path, url })
+  }
+  let search = query ? querySerializer(query) : ''
+  if (search.startsWith('?')) {
+    search = search.substring(1)
+  }
+  if (search) {
+    url += `?${search}`
+  }
+  return url
+}
+
+export const mergeConfigs = (a: Config, b: Config): Config => {
+  const config = { ...a, ...b }
+  if (config.baseUrl?.endsWith('/')) {
+    config.baseUrl = config.baseUrl.substring(0, config.baseUrl.length - 1)
+  }
+  config.headers = mergeHeaders(a.headers, b.headers)
+  return config
+}
+
+export const mergeHeaders = (
+  ...headers: Array<Required<Config>['headers'] | undefined>
+): Headers => {
+  const mergedHeaders = new Headers()
+  for (const header of headers) {
+    if (!header || typeof header !== 'object') {
+      continue
+    }
+
+    const iterator = header instanceof Headers ? header.entries() : Object.entries(header)
+
+    for (const [key, value] of iterator) {
+      if (value === null) {
+        mergedHeaders.delete(key)
+      } else if (Array.isArray(value)) {
+        for (const v of value) {
+          mergedHeaders.append(key, v as string)
+        }
+      } else if (value !== undefined) {
+        // assume object headers are meant to be JSON stringified, i.e. their
+        // content value in OpenAPI specification is 'application/json'
+        mergedHeaders.set(
+          key,
+          typeof value === 'object' ? JSON.stringify(value) : (value as string)
+        )
+      }
+    }
+  }
+  return mergedHeaders
+}
+
+type ErrInterceptor<Err, Res, Req, Options> = (
+  error: Err,
+  response: Res,
+  request: Req,
+  options: Options
+) => Err | Promise<Err>
+
+type ReqInterceptor<Req, Options> = (request: Req, options: Options) => Req | Promise<Req>
+
+type ResInterceptor<Res, Req, Options> = (
+  response: Res,
+  request: Req,
+  options: Options
+) => Res | Promise<Res>
+
+class Interceptors<Interceptor> {
+  _fns: (Interceptor | null)[]
+
+  constructor() {
+    this._fns = []
+  }
+
+  clear() {
+    this._fns = []
+  }
+
+  getInterceptorIndex(id: number | Interceptor): number {
+    if (typeof id === 'number') {
+      return this._fns[id] ? id : -1
+    } else {
+      return this._fns.indexOf(id)
+    }
+  }
+  exists(id: number | Interceptor) {
+    const index = this.getInterceptorIndex(id)
+    return !!this._fns[index]
+  }
+
+  eject(id: number | Interceptor) {
+    const index = this.getInterceptorIndex(id)
+    if (this._fns[index]) {
+      this._fns[index] = null
+    }
+  }
+
+  update(id: number | Interceptor, fn: Interceptor) {
+    const index = this.getInterceptorIndex(id)
+    if (this._fns[index]) {
+      this._fns[index] = fn
+      return id
+    } else {
+      return false
+    }
+  }
+
+  use(fn: Interceptor) {
+    this._fns = [...this._fns, fn]
+    return this._fns.length - 1
+  }
+}
+
+// `createInterceptors()` response, meant for external use as it does not
+// expose internals
+export interface Middleware<Req, Res, Err, Options> {
+  error: Pick<Interceptors<ErrInterceptor<Err, Res, Req, Options>>, 'eject' | 'use'>
+  request: Pick<Interceptors<ReqInterceptor<Req, Options>>, 'eject' | 'use'>
+  response: Pick<Interceptors<ResInterceptor<Res, Req, Options>>, 'eject' | 'use'>
+}
+
+// do not add `Middleware` as return type so we can use _fns internally
+export const createInterceptors = <Req, Res, Err, Options>() => ({
+  error: new Interceptors<ErrInterceptor<Err, Res, Req, Options>>(),
+  request: new Interceptors<ReqInterceptor<Req, Options>>(),
+  response: new Interceptors<ResInterceptor<Res, Req, Options>>()
+})
+
+const defaultQuerySerializer = createQuerySerializer({
+  allowReserved: false,
+  array: {
+    explode: true,
+    style: 'form'
+  },
+  object: {
+    explode: true,
+    style: 'deepObject'
+  }
+})
+
+const defaultHeaders = {
+  'Content-Type': 'application/json'
+}
+
+export const createConfig = <T extends ClientOptions = ClientOptions>(
+  override: Config<Omit<ClientOptions, keyof T> & T> = {}
+): Config<Omit<ClientOptions, keyof T> & T> => ({
+  ...jsonBodySerializer,
+  headers: defaultHeaders,
+  parseAs: 'auto',
+  querySerializer: defaultQuerySerializer,
+  ...override
+})

examples/openapi-ts-tanstack-vue-query/src/client/core/auth.ts

···
+export type AuthToken = string | undefined
+
+export interface Auth {
+  /**
+   * Which part of the request do we use to send the auth?
+   *
+   * @default 'header'
+   */
+  in?: 'header' | 'query' | 'cookie'
+  /**
+   * Header or query parameter name.
+   *
+   * @default 'Authorization'
+   */
+  name?: string
+  scheme?: 'basic' | 'bearer'
+  type: 'apiKey' | 'http'
+}
+
+export const getAuthToken = async (
+  auth: Auth,
+  callback: ((auth: Auth) => Promise<AuthToken> | AuthToken) | AuthToken
+): Promise<string | undefined> => {
+  const token = typeof callback === 'function' ? await callback(auth) : callback
+
+  if (!token) {
+    return
+  }
+
+  if (auth.scheme === 'bearer') {
+    return `Bearer ${token}`
+  }
+
+  if (auth.scheme === 'basic') {
+    return `Basic ${btoa(token)}`
+  }
+
+  return token
+}

examples/openapi-ts-tanstack-vue-query/src/client/core/bodySerializer.ts

···
+import type { ArrayStyle, ObjectStyle, SerializerOptions } from './pathSerializer'
+
+export type QuerySerializer = (query: Record<string, unknown>) => string
+
+export type BodySerializer = (body: any) => any
+
+export interface QuerySerializerOptions {
+  allowReserved?: boolean
+  array?: SerializerOptions<ArrayStyle>
+  object?: SerializerOptions<ObjectStyle>
+}
+
+const serializeFormDataPair = (data: FormData, key: string, value: unknown) => {
+  if (typeof value === 'string' || value instanceof Blob) {
+    data.append(key, value)
+  } else {
+    data.append(key, JSON.stringify(value))
+  }
+}
+
+const serializeUrlSearchParamsPair = (data: URLSearchParams, key: string, value: unknown) => {
+  if (typeof value === 'string') {
+    data.append(key, value)
+  } else {
+    data.append(key, JSON.stringify(value))
+  }
+}
+
+export const formDataBodySerializer = {
+  bodySerializer: <T extends Record<string, any> | Array<Record<string, any>>>(body: T) => {
+    const data = new FormData()
+
+    Object.entries(body).forEach(([key, value]) => {
+      if (value === undefined || value === null) {
+        return
+      }
+      if (Array.isArray(value)) {
+        value.forEach((v) => serializeFormDataPair(data, key, v))
+      } else {
+        serializeFormDataPair(data, key, value)
+      }
+    })
+
+    return data
+  }
+}
+
+export const jsonBodySerializer = {
+  bodySerializer: <T>(body: T) =>
+    JSON.stringify(body, (key, value) => (typeof value === 'bigint' ? value.toString() : value))
+}
+
+export const urlSearchParamsBodySerializer = {
+  bodySerializer: <T extends Record<string, any> | Array<Record<string, any>>>(body: T) => {
+    const data = new URLSearchParams()
+
+    Object.entries(body).forEach(([key, value]) => {
+      if (value === undefined || value === null) {
+        return
+      }
+      if (Array.isArray(value)) {
+        value.forEach((v) => serializeUrlSearchParamsPair(data, key, v))
+      } else {
+        serializeUrlSearchParamsPair(data, key, value)
+      }
+    })
+
+    return data.toString()
+  }
+}

examples/openapi-ts-tanstack-vue-query/src/client/core/params.ts

···
+type Slot = 'body' | 'headers' | 'path' | 'query'
+
+export type Field =
+  | {
+      in: Exclude<Slot, 'body'>
+      key: string
+      map?: string
+    }
+  | {
+      in: Extract<Slot, 'body'>
+      key?: string
+      map?: string
+    }
+
+export interface Fields {
+  allowExtra?: Partial<Record<Slot, boolean>>
+  args?: ReadonlyArray<Field>
+}
+
+export type FieldsConfig = ReadonlyArray<Field | Fields>
+
+const extraPrefixesMap: Record<string, Slot> = {
+  $body_: 'body',
+  $headers_: 'headers',
+  $path_: 'path',
+  $query_: 'query'
+}
+const extraPrefixes = Object.entries(extraPrefixesMap)
+
+type KeyMap = Map<
+  string,
+  {
+    in: Slot
+    map?: string
+  }
+>
+
+const buildKeyMap = (fields: FieldsConfig, map?: KeyMap): KeyMap => {
+  if (!map) {
+    map = new Map()
+  }
+
+  for (const config of fields) {
+    if ('in' in config) {
+      if (config.key) {
+        map.set(config.key, {
+          in: config.in,
+          map: config.map
+        })
+      }
+    } else if (config.args) {
+      buildKeyMap(config.args, map)
+    }
+  }
+
+  return map
+}
+
+interface Params {
+  body: unknown
+  headers: Record<string, unknown>
+  path: Record<string, unknown>
+  query: Record<string, unknown>
+}
+
+const stripEmptySlots = (params: Params) => {
+  for (const [slot, value] of Object.entries(params)) {
+    if (value && typeof value === 'object' && !Object.keys(value).length) {
+      delete params[slot as Slot]
+    }
+  }
+}
+
+export const buildClientParams = (args: ReadonlyArray<unknown>, fields: FieldsConfig) => {
+  const params: Params = {
+    body: {},
+    headers: {},
+    path: {},
+    query: {}
+  }
+
+  const map = buildKeyMap(fields)
+
+  let config: FieldsConfig[number] | undefined
+
+  for (const [index, arg] of args.entries()) {
+    if (fields[index]) {
+      config = fields[index]
+    }
+
+    if (!config) {
+      continue
+    }
+
+    if ('in' in config) {
+      if (config.key) {
+        const field = map.get(config.key)!
+        const name = field.map || config.key
+        ;(params[field.in] as Record<string, unknown>)[name] = arg
+      } else {
+        params.body = arg
+      }
+    } else {
+      for (const [key, value] of Object.entries(arg ?? {})) {
+        const field = map.get(key)
+
+        if (field) {
+          const name = field.map || key
+          ;(params[field.in] as Record<string, unknown>)[name] = value
+        } else {
+          const extra = extraPrefixes.find(([prefix]) => key.startsWith(prefix))
+
+          if (extra) {
+            const [prefix, slot] = extra
+            ;(params[slot] as Record<string, unknown>)[key.slice(prefix.length)] = value
+          } else {
+            for (const [slot, allowed] of Object.entries(config.allowExtra ?? {})) {
+              if (allowed) {
+                ;(params[slot as Slot] as Record<string, unknown>)[key] = value
+                break
+              }
+            }
+          }
+        }
+      }
+    }
+  }
+
+  stripEmptySlots(params)
+
+  return params
+}

examples/openapi-ts-tanstack-vue-query/src/client/core/pathSerializer.ts

···
+interface SerializeOptions<T> extends SerializePrimitiveOptions, SerializerOptions<T> {}
+
+interface SerializePrimitiveOptions {
+  allowReserved?: boolean
+  name: string
+}
+
+export interface SerializerOptions<T> {
+  /**
+   * @default true
+   */
+  explode: boolean
+  style: T
+}
+
+export type ArrayStyle = 'form' | 'spaceDelimited' | 'pipeDelimited'
+export type ArraySeparatorStyle = ArrayStyle | MatrixStyle
+type MatrixStyle = 'label' | 'matrix' | 'simple'
+export type ObjectStyle = 'form' | 'deepObject'
+type ObjectSeparatorStyle = ObjectStyle | MatrixStyle
+
+interface SerializePrimitiveParam extends SerializePrimitiveOptions {
+  value: string
+}
+
+export const separatorArrayExplode = (style: ArraySeparatorStyle) => {
+  switch (style) {
+    case 'label':
+      return '.'
+    case 'matrix':
+      return ';'
+    case 'simple':
+      return ','
+    default:
+      return '&'
+  }
+}
+
+export const separatorArrayNoExplode = (style: ArraySeparatorStyle) => {
+  switch (style) {
+    case 'form':
+      return ','
+    case 'pipeDelimited':
+      return '|'
+    case 'spaceDelimited':
+      return '%20'
+    default:
+      return ','
+  }
+}
+
+export const separatorObjectExplode = (style: ObjectSeparatorStyle) => {
+  switch (style) {
+    case 'label':
+      return '.'
+    case 'matrix':
+      return ';'
+    case 'simple':
+      return ','
+    default:
+      return '&'
+  }
+}
+
+export const serializeArrayParam = ({
+  allowReserved,
+  explode,
+  name,
+  style,
+  value
+}: SerializeOptions<ArraySeparatorStyle> & {
+  value: unknown[]
+}) => {
+  if (!explode) {
+    const joinedValues = (
+      allowReserved ? value : value.map((v) => encodeURIComponent(v as string))
+    ).join(separatorArrayNoExplode(style))
+    switch (style) {
+      case 'label':
+        return `.${joinedValues}`
+      case 'matrix':
+        return `;${name}=${joinedValues}`
+      case 'simple':
+        return joinedValues
+      default:
+        return `${name}=${joinedValues}`
+    }
+  }
+
+  const separator = separatorArrayExplode(style)
+  const joinedValues = value
+    .map((v) => {
+      if (style === 'label' || style === 'simple') {
+        return allowReserved ? v : encodeURIComponent(v as string)
+      }
+
+      return serializePrimitiveParam({
+        allowReserved,
+        name,
+        value: v as string
+      })
+    })
+    .join(separator)
+  return style === 'label' || style === 'matrix' ? separator + joinedValues : joinedValues
+}
+
+export const serializePrimitiveParam = ({
+  allowReserved,
+  name,
+  value
+}: SerializePrimitiveParam) => {
+  if (value === undefined || value === null) {
+    return ''
+  }
+
+  if (typeof value === 'object') {
+    throw new Error(
+      'Deeply-nested arrays/objects aren’t supported. Provide your own `querySerializer()` to handle these.'
+    )
+  }
+
+  return `${name}=${allowReserved ? value : encodeURIComponent(value)}`
+}
+
+export const serializeObjectParam = ({
+  allowReserved,
+  explode,
+  name,
+  style,
+  value,
+  valueOnly
+}: SerializeOptions<ObjectSeparatorStyle> & {
+  value: Record<string, unknown> | Date
+  valueOnly?: boolean
+}) => {
+  if (value instanceof Date) {
+    return valueOnly ? value.toISOString() : `${name}=${value.toISOString()}`
+  }
+
+  if (style !== 'deepObject' && !explode) {
+    let values: string[] = []
+    Object.entries(value).forEach(([key, v]) => {
+      values = [...values, key, allowReserved ? (v as string) : encodeURIComponent(v as string)]
+    })
+    const joinedValues = values.join(',')
+    switch (style) {
+      case 'form':
+        return `${name}=${joinedValues}`
+      case 'label':
+        return `.${joinedValues}`
+      case 'matrix':
+        return `;${name}=${joinedValues}`
+      default:
+        return joinedValues
+    }
+  }
+
+  const separator = separatorObjectExplode(style)
+  const joinedValues = Object.entries(value)
+    .map(([key, v]) =>
+      serializePrimitiveParam({
+        allowReserved,
+        name: style === 'deepObject' ? `${name}[${key}]` : key,
+        value: v as string
+      })
+    )
+    .join(separator)
+  return style === 'label' || style === 'matrix' ? separator + joinedValues : joinedValues
+}

examples/openapi-ts-tanstack-vue-query/src/client/core/types.ts

···
+import type { Auth, AuthToken } from './auth'
+import type { BodySerializer, QuerySerializer, QuerySerializerOptions } from './bodySerializer'
+
+export interface Client<RequestFn = never, Config = unknown, MethodFn = never, BuildUrlFn = never> {
+  /**
+   * Returns the final request URL.
+   */
+  buildUrl: BuildUrlFn
+  connect: MethodFn
+  delete: MethodFn
+  get: MethodFn
+  getConfig: () => Config
+  head: MethodFn
+  options: MethodFn
+  patch: MethodFn
+  post: MethodFn
+  put: MethodFn
+  request: RequestFn
+  setConfig: (config: Config) => Config
+  trace: MethodFn
+}
+
+export interface Config {
+  /**
+   * Auth token or a function returning auth token. The resolved value will be
+   * added to the request payload as defined by its `security` array.
+   */
+  auth?: ((auth: Auth) => Promise<AuthToken> | AuthToken) | AuthToken
+  /**
+   * A function for serializing request body parameter. By default,
+   * {@link JSON.stringify()} will be used.
+   */
+  bodySerializer?: BodySerializer | null
+  /**
+   * An object containing any HTTP headers that you want to pre-populate your
+   * `Headers` object with.
+   *
+   * {@link https://developer.mozilla.org/docs/Web/API/Headers/Headers#init See more}
+   */
+  headers?:
+    | RequestInit['headers']
+    | Record<
+        string,
+        string | number | boolean | (string | number | boolean)[] | null | undefined | unknown
+      >
+  /**
+   * The request method.
+   *
+   * {@link https://developer.mozilla.org/docs/Web/API/fetch#method See more}
+   */
+  method?: 'CONNECT' | 'DELETE' | 'GET' | 'HEAD' | 'OPTIONS' | 'PATCH' | 'POST' | 'PUT' | 'TRACE'
+  /**
+   * A function for serializing request query parameters. By default, arrays
+   * will be exploded in form style, objects will be exploded in deepObject
+   * style, and reserved characters are percent-encoded.
+   *
+   * This method will have no effect if the native `paramsSerializer()` Axios
+   * API function is used.
+   *
+   * {@link https://swagger.io/docs/specification/serialization/#query View examples}
+   */
+  querySerializer?: QuerySerializer | QuerySerializerOptions
+  /**
+   * A function transforming response data before it's returned. This is useful
+   * for post-processing data, e.g. converting ISO strings into Date objects.
+   */
+  responseTransformer?: (data: unknown) => Promise<unknown>
+  /**
+   * A function validating response data. This is useful if you want to ensure
+   * the response conforms to the desired shape, so it can be safely passed to
+   * the transformers and returned to the user.
+   */
+  responseValidator?: (data: unknown) => Promise<unknown>
+}

examples/openapi-ts-tanstack-vue-query/src/client/sdk.gen.ts

···
 // This file is auto-generated by @hey-api/openapi-ts
 
-import type { Client, Options as ClientOptions, TDataShape } from '@hey-api/client-fetch'
-
+import type { Client, Options as ClientOptions, TDataShape } from './client'
 import { client as _heyApiClient } from './client.gen'
 import type {
   AddPetData,
···
     ...options,
     headers: {
       'Content-Type': 'application/json',
-      ...options?.headers
+      ...options.headers
     }
   })
 
···
     ...options,
     headers: {
       'Content-Type': 'application/json',
-      ...options?.headers
+      ...options.headers
     }
   })
 
···
     ...options,
     headers: {
       'Content-Type': 'application/octet-stream',
-      ...options?.headers
+      ...options.headers
     }
   })
 
···
     ...options,
     headers: {
       'Content-Type': 'application/json',
-      ...options?.headers
+      ...options.headers
     }
   })

examples/openapi-ts-tanstack-vue-query/src/views/TanstackExample.vue

···
 <script lang="ts" setup>
 import type { Pet } from '@/client'
+import { createClient } from '@client/client'
 import { PetSchema } from '@/client/schemas.gen'
 import {
   addPetMutation,
   getPetByIdOptions,
   updatePetMutation
 } from '@/client/@tanstack/vue-query.gen'
-import { createClient } from '@hey-api/client-fetch'
 import { useMutation, useQuery, useQueryClient } from '@tanstack/vue-query'
 import { computed, ref, watch } from 'vue'
 

package.json

···
     "@changesets/changelog-github": "0.5.0",
     "@changesets/cli": "2.27.8",
     "@config/vite-base": "workspace:*",
-    "@hey-api/client-axios": "workspace:*",
     "@hey-api/client-custom": "workspace:*",
-    "@hey-api/client-fetch": "workspace:*",
-    "@hey-api/client-next": "workspace:*",
     "@hey-api/client-nuxt": "workspace:*",
     "@types/node": "22.10.5",
     "@typescript-eslint/eslint-plugin": "8.29.1",

packages/client-custom/package.json

···
   },
   "devDependencies": {
     "@config/vite-base": "workspace:*",
-    "@hey-api/client-core": "workspace:*",
     "@hey-api/openapi-ts": "workspace:*"
   }
 }

packages/client-nuxt/package.json

···
   },
   "devDependencies": {
     "@config/vite-base": "workspace:*",
-    "@hey-api/client-core": "workspace:*",
     "@hey-api/openapi-ts": "workspace:*",
     "@nuxt/test-utils": "3.17.2",
     "vite": "6.2.7",

packages/openapi-ts/README.md

···
 ```sh
 npx @hey-api/openapi-ts \
   -i https://get.heyapi.dev/hey-api/backend \
-  -o src/client \
-  -c @hey-api/client-fetch
+  -o src/client
 ```
 
 Congratulations on creating your first client! 🎉 You can learn more about the generated files on the [Output](https://heyapi.dev/openapi-ts/output) page.
-
-Before you can make API requests with the client you've just created, you need to install `@hey-api/client-fetch` and configure it.
 
 ## Installation
 
 #### npm
 
 ```sh
-npm install @hey-api/client-fetch && npm install @hey-api/openapi-ts -D
+npm install @hey-api/openapi-ts -D
 ```
 
 #### pnpm
 
 ```sh
-pnpm add @hey-api/client-fetch && pnpm add @hey-api/openapi-ts -D
+pnpm add @hey-api/openapi-ts -D
 ```
 
 #### yarn
 
 ```sh
-yarn add @hey-api/client-fetch && yarn add @hey-api/openapi-ts -D
+yarn add @hey-api/openapi-ts -D
 ```
 
 #### bun
 
 ```sh
-bun add @hey-api/client-fetch && bun add @hey-api/openapi-ts -D
+bun add @hey-api/openapi-ts -D
 ```
 
 We recommend pinning an exact version so you can safely upgrade when you're ready. This package is in [initial development](https://semver.org/spec/v0.1.0.html#spec-item-5) and its API might change before v1.
···
 createClient({
   input: 'https://get.heyapi.dev/hey-api/backend',
   output: 'src/client',
-  plugins: ['@hey-api/client-fetch'],
 });
 ```
 
···
 export default defineConfig({
   input: 'https://get.heyapi.dev/hey-api/backend',
   output: 'src/client',
-  plugins: ['@hey-api/client-fetch'],
 });
 ```
 
···
 module.exports = {
   input: 'https://get.heyapi.dev/hey-api/backend',
   output: 'src/client',
-  plugins: ['@hey-api/client-fetch'],
 };
 ```
 
···
 export default {
   input: 'https://get.heyapi.dev/hey-api/backend',
   output: 'src/client',
-  plugins: ['@hey-api/client-fetch'],
 };
 ```
 

packages/openapi-ts/package.json

···
   },
   "devDependencies": {
     "@config/vite-base": "workspace:*",
-    "@hey-api/client-core": "workspace:*",
     "@types/cross-spawn": "6.0.6",
     "@types/express": "4.17.21",
     "axios": "1.8.2",

pnpm-lock.yaml

···
       '@config/vite-base':
         specifier: workspace:*
         version: link:packages/config-vite-base
-      '@hey-api/client-axios':
-        specifier: workspace:*
-        version: link:packages/client-axios
       '@hey-api/client-custom':
         specifier: workspace:*
         version: link:packages/client-custom
-      '@hey-api/client-fetch':
-        specifier: workspace:*
-        version: link:packages/client-fetch
-      '@hey-api/client-next':
-        specifier: workspace:*
-        version: link:packages/client-next
       '@hey-api/client-nuxt':
         specifier: workspace:*
         version: link:packages/client-nuxt
···
 
   examples/openapi-ts-axios:
     dependencies:
-      '@hey-api/client-axios':
-        specifier: workspace:*
-        version: link:../../packages/client-axios
       '@radix-ui/react-form':
         specifier: 0.1.1
         version: 0.1.1(@types/react-dom@19.0.1)(@types/react@19.0.1)(react-dom@19.0.0(react@19.0.0))(react@19.0.0)
···
 
   examples/openapi-ts-fastify:
     dependencies:
-      '@hey-api/client-fetch':
-        specifier: workspace:*
-        version: link:../../packages/client-fetch
       fastify:
         specifier: 5.2.0
         version: 5.2.0
···
 
   examples/openapi-ts-fetch:
     dependencies:
-      '@hey-api/client-fetch':
-        specifier: workspace:*
-        version: link:../../packages/client-fetch
       '@radix-ui/react-form':
         specifier: 0.1.1
         version: 0.1.1(@types/react-dom@19.0.1)(@types/react@19.0.1)(react-dom@19.0.0(react@19.0.0))(react@19.0.0)
···
 
   examples/openapi-ts-next:
     dependencies:
-      '@hey-api/client-next':
-        specifier: workspace:*
-        version: link:../../packages/client-next
       next:
         specifier: 15.2.4
         version: 15.2.4(react-dom@19.0.0(react@19.0.0))(react@19.0.0)(sass@1.85.0)
···
 
   examples/openapi-ts-sample:
     dependencies:
-      '@hey-api/client-fetch':
-        specifier: workspace:*
-        version: link:../../packages/client-fetch
       '@radix-ui/react-form':
         specifier: 0.1.1
         version: 0.1.1(@types/react-dom@19.0.1)(@types/react@19.0.1)(react-dom@19.0.0(react@19.0.0))(react@19.0.0)
···
       '@angular/router':
         specifier: ^19.2.0
         version: 19.2.0(@angular/common@19.2.0(@angular/core@19.2.0(rxjs@7.8.1)(zone.js@0.15.0))(rxjs@7.8.1))(@angular/core@19.2.0(rxjs@7.8.1)(zone.js@0.15.0))(@angular/platform-browser@19.2.0(@angular/animations@19.2.0(@angular/core@19.2.0(rxjs@7.8.1)(zone.js@0.15.0)))(@angular/common@19.2.0(@angular/core@19.2.0(rxjs@7.8.1)(zone.js@0.15.0))(rxjs@7.8.1))(@angular/core@19.2.0(rxjs@7.8.1)(zone.js@0.15.0)))(rxjs@7.8.1)
-      '@hey-api/client-fetch':
-        specifier: workspace:*
-        version: link:../../packages/client-fetch
       '@tanstack/angular-query-experimental':
         specifier: 5.73.3
         version: 5.73.3(@angular/common@19.2.0(@angular/core@19.2.0(rxjs@7.8.1)(zone.js@0.15.0))(rxjs@7.8.1))(@angular/core@19.2.0(rxjs@7.8.1)(zone.js@0.15.0))
···
 
   examples/openapi-ts-tanstack-react-query:
     dependencies:
-      '@hey-api/client-fetch':
-        specifier: workspace:*
-        version: link:../../packages/client-fetch
       '@radix-ui/react-form':
         specifier: 0.1.1
         version: 0.1.1(@types/react-dom@19.0.1)(@types/react@19.0.1)(react-dom@19.0.0(react@19.0.0))(react@19.0.0)
···
 
   examples/openapi-ts-tanstack-svelte-query:
     dependencies:
-      '@hey-api/client-fetch':
-        specifier: workspace:*
-        version: link:../../packages/client-fetch
       '@tanstack/svelte-query':
         specifier: 5.73.3
         version: 5.73.3(svelte@5.19.9)
···
 
   examples/openapi-ts-tanstack-vue-query:
     dependencies:
-      '@hey-api/client-fetch':
-        specifier: workspace:*
-        version: link:../../packages/client-fetch
       '@tanstack/vue-query':
         specifier: 5.73.3
         version: 5.73.3(vue@3.5.13(typescript@5.8.3))
···
         specifier: 2.2.0
         version: 2.2.0(typescript@5.8.3)
 
-  packages/client-axios:
-    devDependencies:
-      '@config/vite-base':
-        specifier: workspace:*
-        version: link:../config-vite-base
-      '@hey-api/client-core':
-        specifier: workspace:*
-        version: link:../client-core
-      '@hey-api/openapi-ts':
-        specifier: workspace:*
-        version: link:../openapi-ts
-      axios:
-        specifier: 1.8.2
-        version: 1.8.2
-
-  packages/client-core:
-    devDependencies:
-      '@config/vite-base':
-        specifier: workspace:*
-        version: link:../config-vite-base
-
   packages/client-custom:
     devDependencies:
       '@config/vite-base':
         specifier: workspace:*
         version: link:../config-vite-base
-      '@hey-api/client-core':
-        specifier: workspace:*
-        version: link:../client-core
-      '@hey-api/openapi-ts':
-        specifier: workspace:*
-        version: link:../openapi-ts
-
-  packages/client-fetch:
-    devDependencies:
-      '@config/vite-base':
-        specifier: workspace:*
-        version: link:../config-vite-base
-      '@hey-api/client-core':
-        specifier: workspace:*
-        version: link:../client-core
-      '@hey-api/openapi-ts':
-        specifier: workspace:*
-        version: link:../openapi-ts
-
-  packages/client-next:
-    devDependencies:
-      '@config/vite-base':
-        specifier: workspace:*
-        version: link:../config-vite-base
-      '@hey-api/client-core':
-        specifier: workspace:*
-        version: link:../client-core
       '@hey-api/openapi-ts':
         specifier: workspace:*
         version: link:../openapi-ts
···
       '@config/vite-base':
         specifier: workspace:*
         version: link:../config-vite-base
-      '@hey-api/client-core':
-        specifier: workspace:*
-        version: link:../client-core
       '@hey-api/openapi-ts':
         specifier: workspace:*
         version: link:../openapi-ts
···
       '@config/vite-base':
         specifier: workspace:*
         version: link:../config-vite-base
-      '@hey-api/client-core':
-        specifier: workspace:*
-        version: link:../client-core
       '@types/cross-spawn':
         specifier: 6.0.6
         version: 6.0.6
···
     devDependencies:
       '@angular-devkit/build-angular':
         specifier: 19.2.0
-        version: 19.2.0(@angular/compiler-cli@19.2.0(@angular/compiler@19.2.0(@angular/core@19.2.0(rxjs@7.8.1)(zone.js@0.15.0)))(typescript@5.8.3))(@angular/compiler@19.2.0(@angular/core@19.2.0(rxjs@7.8.1)(zone.js@0.15.0)))(@types/node@22.10.5)(chokidar@4.0.3)(jiti@2.4.2)(karma@6.4.4)(tailwindcss@3.4.9(ts-node@10.9.2(@types/node@22.10.5)(typescript@5.8.3)))(typescript@5.8.3)(vite@5.4.19(@types/node@22.10.5)(less@4.2.2)(sass@1.85.0)(terser@5.39.0))(yaml@2.8.0)
+        version: 19.2.0(@angular/compiler-cli@19.2.0(@angular/compiler@19.2.0(@angular/core@19.2.0(rxjs@7.8.1)(zone.js@0.15.0)))(typescript@5.8.3))(@angular/compiler@19.2.0(@angular/core@19.2.0(rxjs@7.8.1)(zone.js@0.15.0)))(@types/node@22.10.5)(chokidar@4.0.3)(jiti@2.4.2)(karma@6.4.4)(tailwindcss@3.4.9(ts-node@10.9.2(@types/node@22.10.5)(typescript@5.8.3)))(typescript@5.8.3)(vite@6.2.7(@types/node@22.10.5)(jiti@2.4.2)(less@4.2.2)(sass@1.85.0)(terser@5.39.0)(yaml@2.8.0))(yaml@2.8.0)
       '@angular/animations':
         specifier: 19.2.0
         version: 19.2.0(@angular/core@19.2.0(rxjs@7.8.1)(zone.js@0.15.0))
···
         version: 3.3.2
       nuxt:
         specifier: 3.14.1592
-        version: 3.14.1592(@parcel/watcher@2.5.1)(@types/node@22.10.5)(db0@0.3.1)(encoding@0.1.13)(eslint@9.17.0(jiti@2.4.2))(ioredis@5.6.0)(less@4.2.2)(magicast@0.3.5)(optionator@0.9.4)(rollup@4.41.1)(sass@1.85.0)(terser@5.39.0)(typescript@5.8.3)(vite@5.4.19(@types/node@22.10.5)(less@4.2.2)(sass@1.85.0)(terser@5.39.0))
+        version: 3.14.1592(@parcel/watcher@2.5.1)(@types/node@22.10.5)(db0@0.3.1)(encoding@0.1.13)(eslint@9.17.0(jiti@2.4.2))(ioredis@5.6.0)(less@4.2.2)(magicast@0.3.5)(optionator@0.9.4)(rollup@4.41.1)(sass@1.85.0)(terser@5.39.0)(typescript@5.8.3)(vite@6.2.7(@types/node@22.10.5)(jiti@2.4.2)(less@4.2.2)(sass@1.85.0)(terser@5.39.0)(yaml@2.8.0))
       prettier:
         specifier: 3.4.2
         version: 3.4.2
···
     transitivePeerDependencies:
       - chokidar
 
-  '@angular-devkit/build-angular@19.2.0(@angular/compiler-cli@19.2.0(@angular/compiler@19.2.0(@angular/core@19.2.0(rxjs@7.8.1)(zone.js@0.15.0)))(typescript@5.8.3))(@angular/compiler@19.2.0(@angular/core@19.2.0(rxjs@7.8.1)(zone.js@0.15.0)))(@types/node@22.10.5)(chokidar@4.0.3)(jiti@2.4.2)(karma@6.4.4)(tailwindcss@3.4.9(ts-node@10.9.2(@types/node@22.10.5)(typescript@5.8.3)))(typescript@5.8.3)(vite@5.4.19(@types/node@22.10.5)(less@4.2.2)(sass@1.85.0)(terser@5.39.0))(yaml@2.8.0)':
+  '@angular-devkit/build-angular@19.2.0(@angular/compiler-cli@19.2.0(@angular/compiler@19.2.0(@angular/core@19.2.0(rxjs@7.8.1)(zone.js@0.15.0)))(typescript@5.8.3))(@angular/compiler@19.2.0(@angular/core@19.2.0(rxjs@7.8.1)(zone.js@0.15.0)))(@types/node@22.10.5)(chokidar@4.0.3)(jiti@2.4.2)(karma@6.4.4)(tailwindcss@3.4.9(ts-node@10.9.2(@types/node@22.10.5)(typescript@5.8.3)))(typescript@5.8.3)(vite@6.1.0(@types/node@22.10.5)(jiti@2.4.2)(less@4.2.2)(sass@1.85.0)(terser@5.39.0)(yaml@2.8.0))(yaml@2.8.0)':
     dependencies:
       '@ampproject/remapping': 2.3.0
       '@angular-devkit/architect': 0.1902.0(chokidar@4.0.3)
-      '@angular-devkit/build-webpack': 0.1902.0(chokidar@4.0.3)(webpack-dev-server@5.2.0(webpack@5.98.0))(webpack@5.98.0(esbuild@0.25.0))
+      '@angular-devkit/build-webpack': 0.1902.0(chokidar@4.0.3)(webpack-dev-server@5.2.0(webpack@5.98.0(esbuild@0.25.0)))(webpack@5.98.0(esbuild@0.25.0))
       '@angular-devkit/core': 19.2.0(chokidar@4.0.3)
       '@angular/build': 19.2.0(@angular/compiler-cli@19.2.0(@angular/compiler@19.2.0(@angular/core@19.2.0(rxjs@7.8.1)(zone.js@0.15.0)))(typescript@5.8.3))(@angular/compiler@19.2.0(@angular/core@19.2.0(rxjs@7.8.1)(zone.js@0.15.0)))(@types/node@22.10.5)(chokidar@4.0.3)(jiti@2.4.2)(karma@6.4.4)(less@4.2.2)(postcss@8.5.2)(tailwindcss@3.4.9(ts-node@10.9.2(@types/node@22.10.5)(typescript@5.8.3)))(terser@5.39.0)(typescript@5.8.3)(yaml@2.8.0)
       '@angular/compiler-cli': 19.2.0(@angular/compiler@19.2.0(@angular/core@19.2.0(rxjs@7.8.1)(zone.js@0.15.0)))(typescript@5.8.3)
···
       '@babel/runtime': 7.26.9
       '@discoveryjs/json-ext': 0.6.3
       '@ngtools/webpack': 19.2.0(@angular/compiler-cli@19.2.0(@angular/compiler@19.2.0(@angular/core@19.2.0(rxjs@7.8.1)(zone.js@0.15.0)))(typescript@5.8.3))(typescript@5.8.3)(webpack@5.98.0(esbuild@0.25.0))
-      '@vitejs/plugin-basic-ssl': 1.2.0(vite@5.4.19(@types/node@22.10.5)(less@4.2.2)(sass@1.85.0)(terser@5.39.0))
+      '@vitejs/plugin-basic-ssl': 1.2.0(vite@6.1.0(@types/node@22.10.5)(jiti@2.4.2)(less@4.2.2)(sass@1.85.0)(terser@5.39.0)(yaml@2.8.0))
       ansi-colors: 4.1.3
       autoprefixer: 10.4.20(postcss@8.5.2)
       babel-loader: 9.2.1(@babel/core@7.26.9)(webpack@5.98.0(esbuild@0.25.0))
···
       tree-kill: 1.2.2
       tslib: 2.8.1
       typescript: 5.8.3
-      webpack: 5.98.0(esbuild@0.25.0)
-      webpack-dev-middleware: 7.4.2(webpack@5.98.0)
-      webpack-dev-server: 5.2.0(webpack@5.98.0)
+      webpack: 5.98.0(esbuild@0.25.2)
+      webpack-dev-middleware: 7.4.2(webpack@5.98.0(esbuild@0.25.0))
+      webpack-dev-server: 5.2.0(webpack@5.98.0(esbuild@0.25.0))
       webpack-merge: 6.0.1
       webpack-subresource-integrity: 5.1.0(webpack@5.98.0(esbuild@0.25.0))
     optionalDependencies:
···
       - webpack-cli
       - yaml
 
-  '@angular-devkit/build-angular@19.2.0(@angular/compiler-cli@19.2.0(@angular/compiler@19.2.0(@angular/core@19.2.0(rxjs@7.8.1)(zone.js@0.15.0)))(typescript@5.8.3))(@angular/compiler@19.2.0(@angular/core@19.2.0(rxjs@7.8.1)(zone.js@0.15.0)))(@types/node@22.10.5)(chokidar@4.0.3)(jiti@2.4.2)(karma@6.4.4)(tailwindcss@3.4.9(ts-node@10.9.2(@types/node@22.10.5)(typescript@5.8.3)))(typescript@5.8.3)(vite@6.1.0(@types/node@22.10.5)(jiti@2.4.2)(less@4.2.2)(sass@1.85.0)(terser@5.39.0)(yaml@2.8.0))(yaml@2.8.0)':
+  '@angular-devkit/build-angular@19.2.0(@angular/compiler-cli@19.2.0(@angular/compiler@19.2.0(@angular/core@19.2.0(rxjs@7.8.1)(zone.js@0.15.0)))(typescript@5.8.3))(@angular/compiler@19.2.0(@angular/core@19.2.0(rxjs@7.8.1)(zone.js@0.15.0)))(@types/node@22.10.5)(chokidar@4.0.3)(jiti@2.4.2)(karma@6.4.4)(tailwindcss@3.4.9(ts-node@10.9.2(@types/node@22.10.5)(typescript@5.8.3)))(typescript@5.8.3)(vite@6.2.7(@types/node@22.10.5)(jiti@2.4.2)(less@4.2.2)(sass@1.85.0)(terser@5.39.0)(yaml@2.8.0))(yaml@2.8.0)':
     dependencies:
       '@ampproject/remapping': 2.3.0
       '@angular-devkit/architect': 0.1902.0(chokidar@4.0.3)
-      '@angular-devkit/build-webpack': 0.1902.0(chokidar@4.0.3)(webpack-dev-server@5.2.0(webpack@5.98.0(esbuild@0.25.2)))(webpack@5.98.0(esbuild@0.25.0))
+      '@angular-devkit/build-webpack': 0.1902.0(chokidar@4.0.3)(webpack-dev-server@5.2.0(webpack@5.98.0(esbuild@0.25.0)))(webpack@5.98.0(esbuild@0.25.0))
       '@angular-devkit/core': 19.2.0(chokidar@4.0.3)
       '@angular/build': 19.2.0(@angular/compiler-cli@19.2.0(@angular/compiler@19.2.0(@angular/core@19.2.0(rxjs@7.8.1)(zone.js@0.15.0)))(typescript@5.8.3))(@angular/compiler@19.2.0(@angular/core@19.2.0(rxjs@7.8.1)(zone.js@0.15.0)))(@types/node@22.10.5)(chokidar@4.0.3)(jiti@2.4.2)(karma@6.4.4)(less@4.2.2)(postcss@8.5.2)(tailwindcss@3.4.9(ts-node@10.9.2(@types/node@22.10.5)(typescript@5.8.3)))(terser@5.39.0)(typescript@5.8.3)(yaml@2.8.0)
       '@angular/compiler-cli': 19.2.0(@angular/compiler@19.2.0(@angular/core@19.2.0(rxjs@7.8.1)(zone.js@0.15.0)))(typescript@5.8.3)
···
       '@babel/runtime': 7.26.9
       '@discoveryjs/json-ext': 0.6.3
       '@ngtools/webpack': 19.2.0(@angular/compiler-cli@19.2.0(@angular/compiler@19.2.0(@angular/core@19.2.0(rxjs@7.8.1)(zone.js@0.15.0)))(typescript@5.8.3))(typescript@5.8.3)(webpack@5.98.0(esbuild@0.25.0))
-      '@vitejs/plugin-basic-ssl': 1.2.0(vite@6.1.0(@types/node@22.10.5)(jiti@2.4.2)(less@4.2.2)(sass@1.85.0)(terser@5.39.0)(yaml@2.8.0))
+      '@vitejs/plugin-basic-ssl': 1.2.0(vite@6.2.7(@types/node@22.10.5)(jiti@2.4.2)(less@4.2.2)(sass@1.85.0)(terser@5.39.0)(yaml@2.8.0))
       ansi-colors: 4.1.3
       autoprefixer: 10.4.20(postcss@8.5.2)
       babel-loader: 9.2.1(@babel/core@7.26.9)(webpack@5.98.0(esbuild@0.25.0))
···
       tree-kill: 1.2.2
       tslib: 2.8.1
       typescript: 5.8.3
-      webpack: 5.98.0(esbuild@0.25.0)
-      webpack-dev-middleware: 7.4.2(webpack@5.98.0(esbuild@0.25.2))
-      webpack-dev-server: 5.2.0(webpack@5.98.0(esbuild@0.25.2))
+      webpack: 5.98.0(esbuild@0.25.2)
+      webpack-dev-middleware: 7.4.2(webpack@5.98.0(esbuild@0.25.0))
+      webpack-dev-server: 5.2.0(webpack@5.98.0(esbuild@0.25.0))
       webpack-merge: 6.0.1
       webpack-subresource-integrity: 5.1.0(webpack@5.98.0(esbuild@0.25.0))
     optionalDependencies:
···
       - webpack-cli
       - yaml
 
-  '@angular-devkit/build-webpack@0.1902.0(chokidar@4.0.3)(webpack-dev-server@5.2.0(webpack@5.98.0(esbuild@0.25.2)))(webpack@5.98.0(esbuild@0.25.0))':
+  '@angular-devkit/build-webpack@0.1902.0(chokidar@4.0.3)(webpack-dev-server@5.2.0(webpack@5.98.0(esbuild@0.25.0)))(webpack@5.98.0(esbuild@0.25.0))':
     dependencies:
       '@angular-devkit/architect': 0.1902.0(chokidar@4.0.3)
       rxjs: 7.8.1
-      webpack: 5.98.0(esbuild@0.25.0)
-      webpack-dev-server: 5.2.0(webpack@5.98.0(esbuild@0.25.2))
-    transitivePeerDependencies:
-      - chokidar
-
-  '@angular-devkit/build-webpack@0.1902.0(chokidar@4.0.3)(webpack-dev-server@5.2.0(webpack@5.98.0))(webpack@5.98.0(esbuild@0.25.0))':
-    dependencies:
-      '@angular-devkit/architect': 0.1902.0(chokidar@4.0.3)
-      rxjs: 7.8.1
-      webpack: 5.98.0(esbuild@0.25.0)
-      webpack-dev-server: 5.2.0(webpack@5.98.0)
+      webpack: 5.98.0(esbuild@0.25.2)
+      webpack-dev-server: 5.2.0(webpack@5.98.0(esbuild@0.25.0))
     transitivePeerDependencies:
       - chokidar
 
···
     dependencies:
       '@angular/compiler-cli': 19.2.0(@angular/compiler@19.2.0(@angular/core@19.2.0(rxjs@7.8.1)(zone.js@0.15.0)))(typescript@5.8.3)
       typescript: 5.8.3
-      webpack: 5.98.0(esbuild@0.25.0)
+      webpack: 5.98.0(esbuild@0.25.2)
 
   '@nodelib/fs.scandir@2.1.5':
     dependencies:
···
 
   '@nuxt/devalue@2.0.2': {}
 
-  '@nuxt/devtools-kit@1.7.0(magicast@0.3.5)(vite@5.4.19(@types/node@22.10.5)(less@4.2.2)(sass@1.85.0)(terser@5.39.0))':
-    dependencies:
-      '@nuxt/kit': 3.15.4(magicast@0.3.5)
-      '@nuxt/schema': 3.16.2
-      execa: 7.2.0
-      vite: 5.4.19(@types/node@22.10.5)(less@4.2.2)(sass@1.85.0)(terser@5.39.0)
-    transitivePeerDependencies:
-      - magicast
-      - supports-color
-
   '@nuxt/devtools-kit@1.7.0(magicast@0.3.5)(vite@6.2.7(@types/node@22.10.5)(jiti@2.4.2)(less@4.2.2)(sass@1.85.0)(terser@5.39.0)(yaml@2.8.0))':
     dependencies:
       '@nuxt/kit': 3.15.4(magicast@0.3.5)
···
       - utf-8-validate
       - vue
 
-  '@nuxt/devtools@1.7.0(rollup@4.41.1)(vite@5.4.19(@types/node@22.10.5)(less@4.2.2)(sass@1.85.0)(terser@5.39.0))(vue@3.5.13(typescript@5.8.3))':
-    dependencies:
-      '@antfu/utils': 0.7.10
-      '@nuxt/devtools-kit': 1.7.0(magicast@0.3.5)(vite@5.4.19(@types/node@22.10.5)(less@4.2.2)(sass@1.85.0)(terser@5.39.0))
-      '@nuxt/devtools-wizard': 1.7.0
-      '@nuxt/kit': 3.15.4(magicast@0.3.5)
-      '@vue/devtools-core': 7.6.8(vite@5.4.19(@types/node@22.10.5)(less@4.2.2)(sass@1.85.0)(terser@5.39.0))(vue@3.5.13(typescript@5.8.3))
-      '@vue/devtools-kit': 7.6.8
-      birpc: 0.2.19
-      consola: 3.4.0
-      cronstrue: 2.56.0
-      destr: 2.0.3
-      error-stack-parser-es: 0.1.5
-      execa: 7.2.0
-      fast-npm-meta: 0.2.2
-      flatted: 3.3.3
-      get-port-please: 3.1.2
-      hookable: 5.5.3
-      image-meta: 0.2.1
-      is-installed-globally: 1.0.0
-      launch-editor: 2.10.0
-      local-pkg: 0.5.1
-      magicast: 0.3.5
-      nypm: 0.4.1
-      ohash: 1.1.6
-      pathe: 1.1.2
-      perfect-debounce: 1.0.0
-      pkg-types: 1.3.1
-      rc9: 2.1.2
-      scule: 1.3.0
-      semver: 7.7.1
-      simple-git: 3.27.0
-      sirv: 3.0.1
-      tinyglobby: 0.2.12
-      unimport: 3.14.6(rollup@4.41.1)
-      vite: 5.4.19(@types/node@22.10.5)(less@4.2.2)(sass@1.85.0)(terser@5.39.0)
-      vite-plugin-inspect: 0.8.9(@nuxt/kit@3.15.4(magicast@0.3.5))(rollup@4.41.1)(vite@5.4.19(@types/node@22.10.5)(less@4.2.2)(sass@1.85.0)(terser@5.39.0))
-      vite-plugin-vue-inspector: 5.3.1(vite@5.4.19(@types/node@22.10.5)(less@4.2.2)(sass@1.85.0)(terser@5.39.0))
-      which: 3.0.1
-      ws: 8.18.1
-    transitivePeerDependencies:
-      - bufferutil
-      - rollup
-      - supports-color
-      - utf-8-validate
-      - vue
-
   '@nuxt/devtools@1.7.0(rollup@4.41.1)(vite@6.2.7(@types/node@22.10.5)(jiti@2.4.2)(less@4.2.2)(sass@1.85.0)(terser@5.39.0)(yaml@2.8.0))(vue@3.5.13(typescript@5.8.3))':
     dependencies:
       '@antfu/utils': 0.7.10
···
       - rollup
       - supports-color
 
-  '@vitejs/plugin-basic-ssl@1.2.0(vite@5.4.19(@types/node@22.10.5)(less@4.2.2)(sass@1.85.0)(terser@5.39.0))':
-    dependencies:
-      vite: 5.4.19(@types/node@22.10.5)(less@4.2.2)(sass@1.85.0)(terser@5.39.0)
-
   '@vitejs/plugin-basic-ssl@1.2.0(vite@6.1.0(@types/node@22.10.5)(jiti@2.4.2)(less@4.2.2)(sass@1.85.0)(terser@5.39.0)(yaml@2.8.0))':
     dependencies:
       vite: 6.1.0(@types/node@22.10.5)(jiti@2.4.2)(less@4.2.2)(sass@1.85.0)(terser@5.39.0)(yaml@2.8.0)
+
+  '@vitejs/plugin-basic-ssl@1.2.0(vite@6.2.7(@types/node@22.10.5)(jiti@2.4.2)(less@4.2.2)(sass@1.85.0)(terser@5.39.0)(yaml@2.8.0))':
+    dependencies:
+      vite: 6.2.7(@types/node@22.10.5)(jiti@2.4.2)(less@4.2.2)(sass@1.85.0)(terser@5.39.0)(yaml@2.8.0)
 
   '@vitejs/plugin-react@4.4.0-beta.1(vite@6.2.7(@types/node@22.10.5)(jiti@2.4.2)(less@4.2.2)(sass@1.85.0)(terser@5.39.0)(yaml@2.8.0))':
     dependencies:
···
     dependencies:
       '@vue/devtools-kit': 7.7.2
 
-  '@vue/devtools-core@7.6.8(vite@5.4.19(@types/node@22.10.5)(less@4.2.2)(sass@1.85.0)(terser@5.39.0))(vue@3.5.13(typescript@5.8.3))':
-    dependencies:
-      '@vue/devtools-kit': 7.7.2
-      '@vue/devtools-shared': 7.7.2
-      mitt: 3.0.1
-      nanoid: 5.1.5
-      pathe: 1.1.2
-      vite-hot-client: 0.2.4(vite@5.4.19(@types/node@22.10.5)(less@4.2.2)(sass@1.85.0)(terser@5.39.0))
-      vue: 3.5.13(typescript@5.8.3)
-    transitivePeerDependencies:
-      - vite
-
   '@vue/devtools-core@7.6.8(vite@6.2.7(@types/node@22.10.5)(jiti@2.4.2)(less@4.2.2)(sass@1.85.0)(terser@5.39.0)(yaml@2.8.0))(vue@3.5.13(typescript@5.8.3))':
     dependencies:
       '@vue/devtools-kit': 7.7.2
···
       '@babel/core': 7.26.9
       find-cache-dir: 4.0.0
       schema-utils: 4.3.0
-      webpack: 5.98.0(esbuild@0.25.0)
+      webpack: 5.98.0(esbuild@0.25.2)
 
   babel-plugin-polyfill-corejs2@0.4.12(@babel/core@7.26.9):
     dependencies:
···
       normalize-path: 3.0.0
       schema-utils: 4.3.0
       serialize-javascript: 6.0.2
-      webpack: 5.98.0(esbuild@0.25.0)
+      webpack: 5.98.0(esbuild@0.25.2)
 
   core-js-compat@3.41.0:
     dependencies:
···
       postcss-value-parser: 4.2.0
       semver: 7.7.1
     optionalDependencies:
-      webpack: 5.98.0(esbuild@0.25.0)
+      webpack: 5.98.0(esbuild@0.25.2)
 
   css-select@5.1.0:
     dependencies:
···
       '@typescript-eslint/parser': 8.29.1(eslint@9.17.0(jiti@2.4.2))(typescript@5.8.3)
       eslint: 9.17.0(jiti@2.4.2)
       eslint-import-resolver-node: 0.3.9
-      eslint-import-resolver-typescript: 3.8.5(eslint-plugin-import@2.31.0)(eslint@9.17.0(jiti@2.4.2))
-      eslint-plugin-import: 2.31.0(@typescript-eslint/parser@8.29.1(eslint@9.17.0(jiti@2.4.2))(typescript@5.8.3))(eslint-import-resolver-typescript@3.8.5)(eslint@9.17.0(jiti@2.4.2))
+      eslint-import-resolver-typescript: 3.8.5(eslint-plugin-import@2.31.0(@typescript-eslint/parser@8.29.1(eslint@9.17.0(jiti@2.4.2))(typescript@5.8.3))(eslint@9.17.0(jiti@2.4.2)))(eslint@9.17.0(jiti@2.4.2))
+      eslint-plugin-import: 2.31.0(@typescript-eslint/parser@8.29.1(eslint@9.17.0(jiti@2.4.2))(typescript@5.8.3))(eslint-import-resolver-typescript@3.8.5(eslint-plugin-import@2.31.0(@typescript-eslint/parser@8.29.1(eslint@9.17.0(jiti@2.4.2))(typescript@5.8.3))(eslint@9.17.0(jiti@2.4.2)))(eslint@9.17.0(jiti@2.4.2)))(eslint@9.17.0(jiti@2.4.2))
       eslint-plugin-jsx-a11y: 6.10.2(eslint@9.17.0(jiti@2.4.2))
       eslint-plugin-react: 7.37.4(eslint@9.17.0(jiti@2.4.2))
       eslint-plugin-react-hooks: 5.2.0(eslint@9.17.0(jiti@2.4.2))
···
     transitivePeerDependencies:
       - supports-color
 
-  eslint-import-resolver-typescript@3.8.5(eslint-plugin-import@2.31.0)(eslint@9.17.0(jiti@2.4.2)):
+  eslint-import-resolver-typescript@3.8.5(eslint-plugin-import@2.31.0(@typescript-eslint/parser@8.29.1(eslint@9.17.0(jiti@2.4.2))(typescript@5.8.3))(eslint@9.17.0(jiti@2.4.2)))(eslint@9.17.0(jiti@2.4.2)):
     dependencies:
       '@nolyfill/is-core-module': 1.0.39
       debug: 4.4.0(supports-color@9.4.0)
···
       stable-hash: 0.0.4
       tinyglobby: 0.2.12
     optionalDependencies:
-      eslint-plugin-import: 2.31.0(@typescript-eslint/parser@8.29.1(eslint@9.17.0(jiti@2.4.2))(typescript@5.8.3))(eslint-import-resolver-typescript@3.8.5)(eslint@9.17.0(jiti@2.4.2))
+      eslint-plugin-import: 2.31.0(@typescript-eslint/parser@8.29.1(eslint@9.17.0(jiti@2.4.2))(typescript@5.8.3))(eslint-import-resolver-typescript@3.8.5(eslint-plugin-import@2.31.0(@typescript-eslint/parser@8.29.1(eslint@9.17.0(jiti@2.4.2))(typescript@5.8.3))(eslint@9.17.0(jiti@2.4.2)))(eslint@9.17.0(jiti@2.4.2)))(eslint@9.17.0(jiti@2.4.2))
     transitivePeerDependencies:
       - supports-color
 
-  eslint-module-utils@2.12.0(@typescript-eslint/parser@8.29.1(eslint@9.17.0(jiti@2.4.2))(typescript@5.8.3))(eslint-import-resolver-node@0.3.9)(eslint-import-resolver-typescript@3.8.5)(eslint@9.17.0(jiti@2.4.2)):
+  eslint-module-utils@2.12.0(@typescript-eslint/parser@8.29.1(eslint@9.17.0(jiti@2.4.2))(typescript@5.8.3))(eslint-import-resolver-node@0.3.9)(eslint-import-resolver-typescript@3.8.5(eslint-plugin-import@2.31.0(@typescript-eslint/parser@8.29.1(eslint@9.17.0(jiti@2.4.2))(typescript@5.8.3))(eslint@9.17.0(jiti@2.4.2)))(eslint@9.17.0(jiti@2.4.2)))(eslint@9.17.0(jiti@2.4.2)):
     dependencies:
       debug: 3.2.7
     optionalDependencies:
       '@typescript-eslint/parser': 8.29.1(eslint@9.17.0(jiti@2.4.2))(typescript@5.8.3)
       eslint: 9.17.0(jiti@2.4.2)
       eslint-import-resolver-node: 0.3.9
-      eslint-import-resolver-typescript: 3.8.5(eslint-plugin-import@2.31.0)(eslint@9.17.0(jiti@2.4.2))
+      eslint-import-resolver-typescript: 3.8.5(eslint-plugin-import@2.31.0(@typescript-eslint/parser@8.29.1(eslint@9.17.0(jiti@2.4.2))(typescript@5.8.3))(eslint@9.17.0(jiti@2.4.2)))(eslint@9.17.0(jiti@2.4.2))
     transitivePeerDependencies:
       - supports-color
 
-  eslint-plugin-import@2.31.0(@typescript-eslint/parser@8.29.1(eslint@9.17.0(jiti@2.4.2))(typescript@5.8.3))(eslint-import-resolver-typescript@3.8.5)(eslint@9.17.0(jiti@2.4.2)):
+  eslint-plugin-import@2.31.0(@typescript-eslint/parser@8.29.1(eslint@9.17.0(jiti@2.4.2))(typescript@5.8.3))(eslint-import-resolver-typescript@3.8.5(eslint-plugin-import@2.31.0(@typescript-eslint/parser@8.29.1(eslint@9.17.0(jiti@2.4.2))(typescript@5.8.3))(eslint@9.17.0(jiti@2.4.2)))(eslint@9.17.0(jiti@2.4.2)))(eslint@9.17.0(jiti@2.4.2)):
     dependencies:
       '@rtsao/scc': 1.1.0
       array-includes: 3.1.8
···
       doctrine: 2.1.0
       eslint: 9.17.0(jiti@2.4.2)
       eslint-import-resolver-node: 0.3.9
-      eslint-module-utils: 2.12.0(@typescript-eslint/parser@8.29.1(eslint@9.17.0(jiti@2.4.2))(typescript@5.8.3))(eslint-import-resolver-node@0.3.9)(eslint-import-resolver-typescript@3.8.5)(eslint@9.17.0(jiti@2.4.2))
+      eslint-module-utils: 2.12.0(@typescript-eslint/parser@8.29.1(eslint@9.17.0(jiti@2.4.2))(typescript@5.8.3))(eslint-import-resolver-node@0.3.9)(eslint-import-resolver-typescript@3.8.5(eslint-plugin-import@2.31.0(@typescript-eslint/parser@8.29.1(eslint@9.17.0(jiti@2.4.2))(typescript@5.8.3))(eslint@9.17.0(jiti@2.4.2)))(eslint@9.17.0(jiti@2.4.2)))(eslint@9.17.0(jiti@2.4.2))
       hasown: 2.0.2
       is-core-module: 2.16.1
       is-glob: 4.0.3
···
     dependencies:
       less: 4.2.2
     optionalDependencies:
-      webpack: 5.98.0(esbuild@0.25.0)
+      webpack: 5.98.0(esbuild@0.25.2)
 
   less@4.2.2:
     dependencies:
···
     dependencies:
       webpack-sources: 3.2.3
     optionalDependencies:
-      webpack: 5.98.0(esbuild@0.25.0)
+      webpack: 5.98.0(esbuild@0.25.2)
 
   light-my-request@6.6.0:
     dependencies:
···
     dependencies:
       schema-utils: 4.3.0
       tapable: 2.2.1
-      webpack: 5.98.0(esbuild@0.25.0)
+      webpack: 5.98.0(esbuild@0.25.2)
 
   minimalistic-assert@1.0.1: {}
 
···
       - vue-tsc
       - xml2js
 
-  nuxt@3.14.1592(@parcel/watcher@2.5.1)(@types/node@22.10.5)(db0@0.3.1)(encoding@0.1.13)(eslint@9.17.0(jiti@2.4.2))(ioredis@5.6.0)(less@4.2.2)(magicast@0.3.5)(optionator@0.9.4)(rollup@4.41.1)(sass@1.85.0)(terser@5.39.0)(typescript@5.8.3)(vite@5.4.19(@types/node@22.10.5)(less@4.2.2)(sass@1.85.0)(terser@5.39.0)):
-    dependencies:
-      '@nuxt/devalue': 2.0.2
-      '@nuxt/devtools': 1.7.0(rollup@4.41.1)(vite@5.4.19(@types/node@22.10.5)(less@4.2.2)(sass@1.85.0)(terser@5.39.0))(vue@3.5.13(typescript@5.8.3))
-      '@nuxt/kit': 3.14.1592(magicast@0.3.5)(rollup@4.41.1)
-      '@nuxt/schema': 3.14.1592(magicast@0.3.5)(rollup@4.41.1)
-      '@nuxt/telemetry': 2.6.5(magicast@0.3.5)
-      '@nuxt/vite-builder': 3.14.1592(@types/node@22.10.5)(eslint@9.17.0(jiti@2.4.2))(less@4.2.2)(magicast@0.3.5)(optionator@0.9.4)(rollup@4.41.1)(sass@1.85.0)(terser@5.39.0)(typescript@5.8.3)(vue@3.5.13(typescript@5.8.3))
-      '@unhead/dom': 1.11.20
-      '@unhead/shared': 1.11.20
-      '@unhead/ssr': 1.11.20
-      '@unhead/vue': 1.11.20(vue@3.5.13(typescript@5.8.3))
-      '@vue/shared': 3.5.13
-      acorn: 8.14.0
-      c12: 2.0.1(magicast@0.3.5)
-      chokidar: 4.0.3
-      compatx: 0.1.8
-      consola: 3.4.0
-      cookie-es: 1.2.2
-      defu: 6.1.4
-      destr: 2.0.3
-      devalue: 5.1.1
-      errx: 0.1.0
-      esbuild: 0.24.2
-      escape-string-regexp: 5.0.0
-      estree-walker: 3.0.3
-      globby: 14.1.0
-      h3: 1.15.1
-      hookable: 5.5.3
-      ignore: 6.0.2
-      impound: 0.2.2(rollup@4.41.1)
-      jiti: 2.4.2
-      klona: 2.0.6
-      knitwork: 1.2.0
-      magic-string: 0.30.17
-      mlly: 1.7.4
-      nanotar: 0.1.1
-      nitropack: 2.11.6(encoding@0.1.13)(typescript@5.8.3)
-      nuxi: 3.22.5
-      nypm: 0.3.12
-      ofetch: 1.4.1
-      ohash: 1.1.6
-      pathe: 1.1.2
-      perfect-debounce: 1.0.0
-      pkg-types: 1.3.1
-      radix3: 1.1.2
-      scule: 1.3.0
-      semver: 7.7.1
-      std-env: 3.8.1
-      strip-literal: 2.1.1
-      tinyglobby: 0.2.10
-      ufo: 1.5.4
-      ultrahtml: 1.5.3
-      uncrypto: 0.1.3
-      unctx: 2.4.1
-      unenv: 1.10.0
-      unhead: 1.11.20
-      unimport: 3.14.6(rollup@4.41.1)
-      unplugin: 1.16.1
-      unplugin-vue-router: 0.10.9(rollup@4.41.1)(vue-router@4.5.0(vue@3.5.13(typescript@5.8.3)))(vue@3.5.13(typescript@5.8.3))
-      unstorage: 1.15.0(db0@0.3.1)(ioredis@5.6.0)
-      untyped: 1.5.2
-      vue: 3.5.13(typescript@5.8.3)
-      vue-bundle-renderer: 2.1.1
-      vue-devtools-stub: 0.1.0
-      vue-router: 4.5.0(vue@3.5.13(typescript@5.8.3))
-    optionalDependencies:
-      '@parcel/watcher': 2.5.1
-      '@types/node': 22.10.5
-    transitivePeerDependencies:
-      - '@azure/app-configuration'
-      - '@azure/cosmos'
-      - '@azure/data-tables'
-      - '@azure/identity'
-      - '@azure/keyvault-secrets'
-      - '@azure/storage-blob'
-      - '@biomejs/biome'
-      - '@capacitor/preferences'
-      - '@deno/kv'
-      - '@electric-sql/pglite'
-      - '@libsql/client'
-      - '@netlify/blobs'
-      - '@planetscale/database'
-      - '@upstash/redis'
-      - '@vercel/blob'
-      - '@vercel/kv'
-      - aws4fetch
-      - better-sqlite3
-      - bufferutil
-      - db0
-      - drizzle-orm
-      - encoding
-      - eslint
-      - idb-keyval
-      - ioredis
-      - less
-      - lightningcss
-      - magicast
-      - meow
-      - mysql2
-      - optionator
-      - rolldown
-      - rollup
-      - sass
-      - sass-embedded
-      - sqlite3
-      - stylelint
-      - stylus
-      - sugarss
-      - supports-color
-      - terser
-      - typescript
-      - uploadthing
-      - utf-8-validate
-      - vite
-      - vls
-      - vti
-      - vue-tsc
-      - xml2js
-
   nuxt@3.14.1592(@parcel/watcher@2.5.1)(@types/node@22.10.5)(db0@0.3.1)(encoding@0.1.13)(eslint@9.17.0(jiti@2.4.2))(ioredis@5.6.0)(less@4.2.2)(magicast@0.3.5)(optionator@0.9.4)(rollup@4.41.1)(sass@1.85.0)(terser@5.39.0)(typescript@5.8.3)(vite@6.2.7(@types/node@22.10.5)(jiti@2.4.2)(less@4.2.2)(sass@1.85.0)(terser@5.39.0)(yaml@2.8.0)):
     dependencies:
       '@nuxt/devalue': 2.0.2
···
       postcss: 8.5.2
       semver: 7.7.1
     optionalDependencies:
-      webpack: 5.98.0(esbuild@0.25.0)
+      webpack: 5.98.0(esbuild@0.25.2)
     transitivePeerDependencies:
       - typescript
 
···
       neo-async: 2.6.2
     optionalDependencies:
       sass: 1.85.0
-      webpack: 5.98.0(esbuild@0.25.0)
+      webpack: 5.98.0(esbuild@0.25.2)
 
   sass@1.85.0:
     dependencies:
···
     dependencies:
       iconv-lite: 0.6.3
       source-map-js: 1.2.1
-      webpack: 5.98.0(esbuild@0.25.0)
+      webpack: 5.98.0(esbuild@0.25.2)
 
   source-map-support@0.5.21:
     dependencies:
···
 
   term-size@2.2.1: {}
 
-  terser-webpack-plugin@5.3.14(esbuild@0.25.0)(webpack@5.98.0):
+  terser-webpack-plugin@5.3.14(esbuild@0.25.2)(webpack@5.98.0(esbuild@0.25.0)):
     dependencies:
       '@jridgewell/trace-mapping': 0.3.25
       jest-worker: 27.5.1
       schema-utils: 4.3.0
       serialize-javascript: 6.0.2
       terser: 5.39.0
-      webpack: 5.98.0(esbuild@0.25.0)
+      webpack: 5.98.0(esbuild@0.25.2)
     optionalDependencies:
-      esbuild: 0.25.0
+      esbuild: 0.25.2
 
   terser@5.39.0:
     dependencies:
···
       '@types/unist': 3.0.3
       vfile-message: 4.0.2
 
-  vite-hot-client@0.2.4(vite@5.4.19(@types/node@22.10.5)(less@4.2.2)(sass@1.85.0)(terser@5.39.0)):
-    dependencies:
-      vite: 5.4.19(@types/node@22.10.5)(less@4.2.2)(sass@1.85.0)(terser@5.39.0)
-
   vite-hot-client@0.2.4(vite@6.2.7(@types/node@22.10.5)(jiti@2.4.2)(less@4.2.2)(sass@1.85.0)(terser@5.39.0)(yaml@2.8.0)):
     dependencies:
       vite: 6.2.7(@types/node@22.10.5)(jiti@2.4.2)(less@4.2.2)(sass@1.85.0)(terser@5.39.0)(yaml@2.8.0)
···
       - rollup
       - supports-color
 
-  vite-plugin-inspect@0.8.9(@nuxt/kit@3.15.4(magicast@0.3.5))(rollup@4.41.1)(vite@5.4.19(@types/node@22.10.5)(less@4.2.2)(sass@1.85.0)(terser@5.39.0)):
-    dependencies:
-      '@antfu/utils': 0.7.10
-      '@rollup/pluginutils': 5.1.4(rollup@4.41.1)
-      debug: 4.4.0(supports-color@9.4.0)
-      error-stack-parser-es: 0.1.5
-      fs-extra: 11.3.0
-      open: 10.1.0
-      perfect-debounce: 1.0.0
-      picocolors: 1.1.1
-      sirv: 3.0.1
-      vite: 5.4.19(@types/node@22.10.5)(less@4.2.2)(sass@1.85.0)(terser@5.39.0)
-    optionalDependencies:
-      '@nuxt/kit': 3.15.4(magicast@0.3.5)
-    transitivePeerDependencies:
-      - rollup
-      - supports-color
-
   vite-plugin-inspect@0.8.9(@nuxt/kit@3.15.4(magicast@0.3.5))(rollup@4.41.1)(vite@6.2.7(@types/node@22.10.5)(jiti@2.4.2)(less@4.2.2)(sass@1.85.0)(terser@5.39.0)(yaml@2.8.0)):
     dependencies:
       '@antfu/utils': 0.7.10
···
       - rollup
       - supports-color
       - vue
-
-  vite-plugin-vue-inspector@5.3.1(vite@5.4.19(@types/node@22.10.5)(less@4.2.2)(sass@1.85.0)(terser@5.39.0)):
-    dependencies:
-      '@babel/core': 7.26.10
-      '@babel/plugin-proposal-decorators': 7.25.9(@babel/core@7.26.10)
-      '@babel/plugin-syntax-import-attributes': 7.26.0(@babel/core@7.26.10)
-      '@babel/plugin-syntax-import-meta': 7.10.4(@babel/core@7.26.10)
-      '@babel/plugin-transform-typescript': 7.26.8(@babel/core@7.26.10)
-      '@vue/babel-plugin-jsx': 1.4.0(@babel/core@7.26.10)
-      '@vue/compiler-dom': 3.5.13
-      kolorist: 1.8.0
-      magic-string: 0.30.17
-      vite: 5.4.19(@types/node@22.10.5)(less@4.2.2)(sass@1.85.0)(terser@5.39.0)
-    transitivePeerDependencies:
-      - supports-color
 
   vite-plugin-vue-inspector@5.3.1(vite@6.2.7(@types/node@22.10.5)(jiti@2.4.2)(less@4.2.2)(sass@1.85.0)(terser@5.39.0)(yaml@2.8.0)):
     dependencies:
···
 
   webidl-conversions@7.0.0: {}
 
-  webpack-dev-middleware@7.4.2(webpack@5.98.0(esbuild@0.25.2)):
-    dependencies:
-      colorette: 2.0.20
-      memfs: 4.17.0
-      mime-types: 2.1.35
-      on-finished: 2.4.1
-      range-parser: 1.2.1
-      schema-utils: 4.3.0
-    optionalDependencies:
-      webpack: 5.98.0(esbuild@0.25.0)
-
-  webpack-dev-middleware@7.4.2(webpack@5.98.0):
+  webpack-dev-middleware@7.4.2(webpack@5.98.0(esbuild@0.25.0)):
     dependencies:
       colorette: 2.0.20
       memfs: 4.17.0
···
       range-parser: 1.2.1
       schema-utils: 4.3.0
     optionalDependencies:
-      webpack: 5.98.0(esbuild@0.25.0)
+      webpack: 5.98.0(esbuild@0.25.2)
 
-  webpack-dev-server@5.2.0(webpack@5.98.0(esbuild@0.25.2)):
+  webpack-dev-server@5.2.0(webpack@5.98.0(esbuild@0.25.0)):
     dependencies:
       '@types/bonjour': 3.5.13
       '@types/connect-history-api-fallback': 1.5.4
···
       serve-index: 1.9.1
       sockjs: 0.3.24
       spdy: 4.0.2
-      webpack-dev-middleware: 7.4.2(webpack@5.98.0(esbuild@0.25.2))
+      webpack-dev-middleware: 7.4.2(webpack@5.98.0(esbuild@0.25.0))
       ws: 8.18.1
     optionalDependencies:
-      webpack: 5.98.0(esbuild@0.25.0)
-    transitivePeerDependencies:
-      - bufferutil
-      - debug
-      - supports-color
-      - utf-8-validate
-
-  webpack-dev-server@5.2.0(webpack@5.98.0):
-    dependencies:
-      '@types/bonjour': 3.5.13
-      '@types/connect-history-api-fallback': 1.5.4
-      '@types/express': 4.17.21
-      '@types/serve-index': 1.9.4
-      '@types/serve-static': 1.15.7
-      '@types/sockjs': 0.3.36
-      '@types/ws': 8.18.0
-      ansi-html-community: 0.0.8
-      bonjour-service: 1.3.0
-      chokidar: 3.6.0
-      colorette: 2.0.20
-      compression: 1.8.0
-      connect-history-api-fallback: 2.0.0
-      express: 4.21.2
-      graceful-fs: 4.2.11
-      http-proxy-middleware: 2.0.7(@types/express@4.17.21)
-      ipaddr.js: 2.2.0
-      launch-editor: 2.10.0
-      open: 10.1.0
-      p-retry: 6.2.1
-      schema-utils: 4.3.0
-      selfsigned: 2.4.1
-      serve-index: 1.9.1
-      sockjs: 0.3.24
-      spdy: 4.0.2
-      webpack-dev-middleware: 7.4.2(webpack@5.98.0)
-      ws: 8.18.1
-    optionalDependencies:
-      webpack: 5.98.0(esbuild@0.25.0)
+      webpack: 5.98.0(esbuild@0.25.2)
     transitivePeerDependencies:
       - bufferutil
       - debug
···
   webpack-subresource-integrity@5.1.0(webpack@5.98.0(esbuild@0.25.0)):
     dependencies:
       typed-assert: 1.0.9
-      webpack: 5.98.0(esbuild@0.25.0)
+      webpack: 5.98.0(esbuild@0.25.2)
 
   webpack-virtual-modules@0.6.2: {}
 
-  webpack@5.98.0(esbuild@0.25.0):
+  webpack@5.98.0(esbuild@0.25.2):
     dependencies:
       '@types/eslint-scope': 3.7.7
       '@types/estree': 1.0.6
···
       neo-async: 2.6.2
       schema-utils: 4.3.0
       tapable: 2.2.1
-      terser-webpack-plugin: 5.3.14(esbuild@0.25.0)(webpack@5.98.0)
+      terser-webpack-plugin: 5.3.14(esbuild@0.25.2)(webpack@5.98.0(esbuild@0.25.0))
       watchpack: 2.4.2
       webpack-sources: 3.2.3
     transitivePeerDependencies: