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// Copyright 2018-2023 the Deno authors. All rights reserved. MIT license.
/** Create a `ReadableStream` from any kind of iterable. * * ```ts * import { readableStreamFromIterable } from "https://deno.land/std@$STD_VERSION/streams/readable_stream_from_iterable.ts"; * * const r1 = readableStreamFromIterable(["foo, bar, baz"]); * const r2 = readableStreamFromIterable(async function* () { * await new Promise(((r) => setTimeout(r, 1000))); * yield "foo"; * await new Promise(((r) => setTimeout(r, 1000))); * yield "bar"; * await new Promise(((r) => setTimeout(r, 1000))); * yield "baz"; * }()); * ``` * * If the produced iterator (`iterable[Symbol.asyncIterator]()` or * `iterable[Symbol.iterator]()`) is a generator, or more specifically is found * to have a `.throw()` method on it, that will be called upon * `readableStream.cancel()`. This is the case for the second input type above: * * ```ts * import { readableStreamFromIterable } from "https://deno.land/std@$STD_VERSION/streams/readable_stream_from_iterable.ts"; * * const r3 = readableStreamFromIterable(async function* () { * try { * yield "foo"; * } catch (error) { * console.log(error); // Error: Cancelled by consumer. * } * }()); * const reader = r3.getReader(); * console.log(await reader.read()); // { value: "foo", done: false } * await reader.cancel(new Error("Cancelled by consumer.")); * ``` */export function readableStreamFromIterable<T>( iterable: Iterable<T> | AsyncIterable<T>,): ReadableStream<T> { const iterator: Iterator<T> | AsyncIterator<T> = (iterable as AsyncIterable<T>)[Symbol.asyncIterator]?.() ?? (iterable as Iterable<T>)[Symbol.iterator]?.(); return new ReadableStream({ async pull(controller) { const { value, done } = await iterator.next(); if (done) { controller.close(); } else { controller.enqueue(value); } }, async cancel(reason) { if (typeof iterator.throw == "function") { try { await iterator.throw(reason); } catch { /* `iterator.throw()` always throws on site. We catch it. */ } } }, });}