Streams: support ReadableStream.from()

[MattiasBuelens]

The Streams standard has been updated with a new utility method ReadableStream.from(asyncIterable), which adapts any sync or async iterable into a ReadableStream.

Specification: https://streams.spec.whatwg.org/#rs-from
Spec change: whatwg/streams#1083
WPT tests: web-platform-tests/wpt#27009

[MattiasBuelens]

This is very similar to Node's Readable.from(iterable), except for Web Streams. And because both Readable and ReadableStream are async iterables and have a static from() method, there's a nice duality for converting them:

import { Readable } from 'node:stream';
import { ReadableStream } from 'node:stream/web';

const nodeReadable = new Readable({ /* ... */ });
const webReadableStreamFromNodeReadable = ReadableStream.from(nodeReadable);

const webReadableStream = new ReadableStream({ /* ... */ });
const nodeReadableFromWebReadableStream = Readable.from(webReadableStream);

Also, Readable.toWeb(nodeReadable) will be equivalent to ReadableStream.from(nodeReadable) (although the former can be optimized specifically for Node streams, whereas the latter is more general).

[debadree25]

Hey! will give this a try hoping to have a PR ready soon!