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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);          }        })();      }    },  });}