35 lines
1.0 KiB
TypeScript
35 lines
1.0 KiB
TypeScript
// Copyright 2018-2023 the Deno authors. All rights reserved. MIT license.
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// This module is browser compatible.
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/**
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* Merge multiple streams into a single one, taking order into account, and each stream
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* will wait for a chunk to enqueue before the next stream can append another chunk.
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* If a stream ends before other ones, the others will be cancelled.
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*/
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export function earlyZipReadableStreams<T>(
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...streams: ReadableStream<T>[]
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): ReadableStream<T> {
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const readers = streams.map((s) => s.getReader());
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return new ReadableStream<T>({
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async start(controller) {
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try {
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loop:
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while (true) {
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for (const reader of readers) {
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const { value, done } = await reader.read();
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if (!done) {
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controller.enqueue(value!);
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} else {
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await Promise.all(readers.map((reader) => reader.cancel()));
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break loop;
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}
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}
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}
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controller.close();
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} catch (e) {
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controller.error(e);
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}
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},
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});
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}
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