import { deferred } from "../async/deferred.ts";
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); } }, });}
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); } }, });}
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); } }, });}