deno.land / std@0.224.0 / streams / early_zip_readable_streams.ts

early_zip_readable_streams.ts
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// Copyright 2018-2024 the Deno authors. All rights reserved. MIT license.// This module is browser compatible.
/** * Merge multiple streams into a single one, taking order into account, and each stream * will wait for a chunk to enqueue before the next stream can append another chunk. * If a stream ends before other ones, the others will be cancelled. * * @example * ```ts * import { earlyZipReadableStreams } from "https://deno.land/std@$STD_VERSION/streams/early_zip_readable_streams.ts"; * * const stream1 = ReadableStream.from(["1", "2", "3"]); * const stream2 = ReadableStream.from(["a", "b", "c"]); * const zippedStream = earlyZipReadableStreams(stream1, stream2); * * await Array.fromAsync(zippedStream); // ["1", "a", "2", "b", "3", "c"]; * ``` */export function earlyZipReadableStreams<T>( ...streams: ReadableStream<T>[]): ReadableStream<T> { const readers = streams.map((s) => s.getReader()); return new ReadableStream<T>({ async start(controller) { try { loop: while (true) { for (const reader of readers) { const { value, done } = await reader.read(); if (!done) { controller.enqueue(value!); } else { await Promise.all(readers.map((reader) => reader.cancel())); break loop; } } } controller.close(); } catch (e) { controller.error(e); } }, });}
std

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Tagged at
6 months ago