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// Copyright 2018-2022 the Deno authors. All rights reserved. MIT license.
import { deferred } from "../async/deferred.ts";
/** * 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. */export function mergeReadableStreams<T>(  ...streams: ReadableStream<T>[]): ReadableStream<T> {  const resolvePromises = streams.map(() => deferred<void>());  return new ReadableStream<T>({    start(controller) {      Promise.all(resolvePromises).then(() => {        controller.close();      });      try {        for (const [key, stream] of Object.entries(streams)) {          (async () => {            for await (const data of stream) {              controller.enqueue(data);            }            resolvePromises[+key].resolve();          })();        }      } catch (e) {        controller.error(e);      }    },  });}
/** * 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 continue adding data in order, * and the finished one will not add any more data. */export function zipReadableStreams<T>(  ...streams: ReadableStream<T>[]): ReadableStream<T> {  const readers = streams.map((s) => s.getReader());  return new ReadableStream<T>({    async start(controller) {      try {        let resolved = 0;        while (resolved != streams.length) {          for (const [key, reader] of Object.entries(readers)) {            const { value, done } = await reader.read();            if (!done) {              controller.enqueue(value!);            } else {              resolved++;              readers.splice(+key, 1);            }          }        }        controller.close();      } catch (e) {        controller.error(e);      }    },  });}
/** * 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. */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);      }    },  });}