oppi.li
source dump of claude code
1const NO_VALUE = Symbol('NO_VALUE')
2
3export async function lastX<A>(as: AsyncGenerator<A>): Promise<A> {
4 let lastValue: A | typeof NO_VALUE = NO_VALUE
5 for await (const a of as) {
6 lastValue = a
7 }
8 if (lastValue === NO_VALUE) {
9 throw new Error('No items in generator')
10 }
11 return lastValue
12}
13
14export async function returnValue<A>(
15 as: AsyncGenerator<unknown, A>,
16): Promise<A> {
17 let e
18 do {
19 e = await as.next()
20 } while (!e.done)
21 return e.value
22}
23
24type QueuedGenerator<A> = {
25 done: boolean | void
26 value: A | void
27 generator: AsyncGenerator<A, void>
28 promise: Promise<QueuedGenerator<A>>
29}
30
31// Run all generators concurrently up to a concurrency cap, yielding values as they come in
32export async function* all<A>(
33 generators: AsyncGenerator<A, void>[],
34 concurrencyCap = Infinity,
35): AsyncGenerator<A, void> {
36 const next = (generator: AsyncGenerator<A, void>) => {
37 const promise: Promise<QueuedGenerator<A>> = generator
38 .next()
39 .then(({ done, value }) => ({
40 done,
41 value,
42 generator,
43 promise,
44 }))
45 return promise
46 }
47 const waiting = [...generators]
48 const promises = new Set<Promise<QueuedGenerator<A>>>()
49
50 // Start initial batch up to concurrency cap
51 while (promises.size < concurrencyCap && waiting.length > 0) {
52 const gen = waiting.shift()!
53 promises.add(next(gen))
54 }
55
56 while (promises.size > 0) {
57 const { done, value, generator, promise } = await Promise.race(promises)
58 promises.delete(promise)
59
60 if (!done) {
61 promises.add(next(generator))
62 // TODO: Clean this up
63 if (value !== undefined) {
64 yield value
65 }
66 } else if (waiting.length > 0) {
67 // Start a new generator when one finishes
68 const nextGen = waiting.shift()!
69 promises.add(next(nextGen))
70 }
71 }
72}
73
74export async function toArray<A>(
75 generator: AsyncGenerator<A, void>,
76): Promise<A[]> {
77 const result: A[] = []
78 for await (const a of generator) {
79 result.push(a)
80 }
81 return result
82}
83
84export async function* fromArray<T>(values: T[]): AsyncGenerator<T, void> {
85 for (const value of values) {
86 yield value
87 }
88}