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// Copyright Node.js contributors. All rights reserved. MIT License.
import { Buffer } from "../buffer.ts";
import Readable from "./readable.ts";
import type { ReadableOptions } from "./readable.ts";
import { ERR_INVALID_ARG_TYPE, ERR_STREAM_NULL_VALUES } from "../_errors.ts";
export default function from(
// deno-lint-ignore no-explicit-any
iterable: Iterable<any> | AsyncIterable<any>,
opts?: ReadableOptions,
) {
let iterator:
// deno-lint-ignore no-explicit-any
| Iterator<any, any, undefined>
// deno-lint-ignore no-explicit-any
| AsyncIterator<any, any, undefined>;
if (typeof iterable === "string" || iterable instanceof Buffer) {
return new Readable({
objectMode: true,
...opts,
read() {
this.push(iterable);
this.push(null);
},
});
}
if (Symbol.asyncIterator in iterable) {
// deno-lint-ignore no-explicit-any
iterator = (iterable as AsyncIterable<any>)[Symbol.asyncIterator]();
} else if (Symbol.iterator in iterable) {
// deno-lint-ignore no-explicit-any
iterator = (iterable as Iterable<any>)[Symbol.iterator]();
} else {
throw new ERR_INVALID_ARG_TYPE("iterable", ["Iterable"], iterable);
}
const readable = new Readable({
objectMode: true,
highWaterMark: 1,
...opts,
});
// Reading boolean to protect against _read
// being called before last iteration completion.
let reading = false;
// needToClose boolean if iterator needs to be explicitly closed
let needToClose = false;
readable._read = function () {
if (!reading) {
reading = true;
next();
}
};
readable._destroy = function (error, cb) {
if (needToClose) {
needToClose = false;
close().then(
() => queueMicrotask(() => cb(error)),
(e) => queueMicrotask(() => cb(error || e)),
);
} else {
cb(error);
}
};
async function close() {
if (typeof iterator.return === "function") {
const { value } = await iterator.return();
await value;
}
}
async function next() {
try {
needToClose = false;
const { value, done } = await iterator.next();
needToClose = !done;
if (done) {
readable.push(null);
} else if (readable.destroyed) {
await close();
} else {
const res = await value;
if (res === null) {
reading = false;
throw new ERR_STREAM_NULL_VALUES();
} else if (readable.push(res)) {
next();
} else {
reading = false;
}
}
} catch (err) {
readable.destroy(err);
}
}
return readable;
}
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