bretton.dev
Coves frontend - a photon fork
1/// <reference types="@sveltejs/kit" />
2/// <reference no-default-lib="true"/>
3/// <reference lib="esnext" />
4/// <reference lib="webworker" />
5
6import { build, files, version } from '$service-worker'
7
8// Create a unique cache name for this deployment
9const CACHE = `cache-${version}`
10
11const ASSETS = [
12 ...build, // the app itself
13 ...files, // everything in `static`
14]
15
16self.addEventListener('install', (event) => {
17 console.info('[i] Installing service worker')
18 // Create a new cache and add all files to it
19 async function addFilesToCache() {
20 const cache = await caches.open(CACHE)
21 await cache.addAll(ASSETS)
22 }
23
24 event.waitUntil(addFilesToCache())
25})
26
27self.addEventListener('activate', (event) => {
28 console.info('[i] Activating service worker')
29 // Remove previous cached data from disk
30 async function deleteOldCaches() {
31 for (const key of await caches.keys()) {
32 if (key !== CACHE) await caches.delete(key)
33 }
34 }
35
36 event.waitUntil(deleteOldCaches())
37})
38
39self.addEventListener('fetch', (e) => {
40 const event = e as FetchEvent
41 // ignore POST requests etc
42 if (event.request.method !== 'GET') return
43
44 async function respond() {
45 const url = new URL(event.request.url)
46 const cache = await caches.open(CACHE)
47
48 // `build`/`files` can always be served from the cache
49 if (ASSETS.includes(url.pathname)) {
50 const response = await cache.match(url.pathname)
51
52 if (response) return response
53 }
54
55 if (url.pathname.includes('/api/')) {
56 return fetch(event.request)
57 }
58
59 // for everything else, try the network first, but
60 // fall back to the cache if we're offline
61 try {
62 const response = await fetch(event.request)
63
64 // if we're offline, fetch can return a value that is not a Response
65 // instead of throwing - and we can't pass this non-Response to respondWith
66 if (!(response instanceof Response)) {
67 throw new Error('invalid response from fetch')
68 }
69
70 if (response.ok) {
71 cache.put(event.request, response.clone())
72 }
73
74 return response
75 } catch (err) {
76 const response = await cache.match(event.request)
77
78 if (response) {
79 return response
80 }
81
82 // if there's no cache, then just error out
83 // as there is nothing we can do to respond to this request
84 throw err
85 }
86 }
87
88 event.respondWith(respond())
89})