| 1 | import { Readable } from 'stream' |
| 2 | import { isAsyncIterable } from './cross' |
| 3 | |
| 4 | // produces as promises resolve, not sequentially |
| 5 | export class AsapStream<T> extends Readable { |
| 6 | finished = false |
| 7 | constructor(private promises: Iterable<Promise<T> | T> | AsyncIterable<Promise<T> | T>) { |
| 8 | super({ objectMode: true }) |
| 9 | } |
| 10 | _read() { |
| 11 | if (this.finished) return |
| 12 | this.finished = true |
| 13 | void (async () => { |
| 14 | const pending: Promise<T>[] = [] |
| 15 | try { |
| 16 | if (isAsyncIterable(this.promises)) { |
| 17 | const iterator = this.promises[Symbol.asyncIterator]() |
| 18 | while (true) { |
| 19 | const { value, done } = await iterator.next() |
| 20 | if (done) break |
| 21 | const promise = Promise.resolve(value) |
| 22 | pending.push(promise) |
| 23 | promise.then(x => x !== undefined && this.push(x), |
| 24 | e => this.emit('error', e) ) |
| 25 | } |
| 26 | } |
| 27 | else { |
| 28 | for (const p of this.promises) { |
| 29 | const promise = Promise.resolve(p) |
| 30 | pending.push(promise) |
| 31 | promise.then(x => x !== undefined && this.push(x), |
| 32 | e => this.emit('error', e) ) |
| 33 | } |
| 34 | } |
| 35 | await Promise.allSettled(pending) |
| 36 | this.push(null) |
| 37 | } |
| 38 | catch (e) { |
| 39 | this.emit('error', e) |
| 40 | this.push(null) |
| 41 | } |
| 42 | })() |
| 43 | } |
| 44 | } |