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// Copyright 2018-2024 the Deno authors. All rights reserved. MIT license.
/** * Merge multiple streams into a single one, not taking order into account. * If a stream ends before other ones, the other will continue adding data, * and the finished one will not add any more data. * * @example * ```ts * import { mergeReadableStreams } from "https://deno.land/std@$STD_VERSION/streams/merge_readable_streams.ts"; * * const stream1 = ReadableStream.from(["1", "2", "3"]); * const stream2 = ReadableStream.from(["a", "b", "c"]); * * // ["2", "c", "a", "b", "3", "1"] * await Array.fromAsync(mergeReadableStreams(stream1, stream2)); * ``` */export function mergeReadableStreams<T>( ...streams: ReadableStream<T>[]): ReadableStream<T> { const resolvePromises = streams.map(() => Promise.withResolvers<void>()); return new ReadableStream<T>({ start(controller) { let mustClose = false; Promise.all(resolvePromises.map(({ promise }) => promise)) .then(() => { controller.close(); }) .catch((error) => { mustClose = true; controller.error(error); }); for (const [index, stream] of streams.entries()) { (async () => { try { for await (const data of stream) { if (mustClose) { break; } controller.enqueue(data); } resolvePromises[index]!.resolve(); } catch (error) { resolvePromises[index]!.reject(error); } })(); } }, });}