sindresorhus / make-asynchronous

Make a synchronous function asynchronous by running it in a worker

make-asynchronous

Make a synchronous function asynchronous by running it in a worker

This makes it super simple to offload some expensive work without having to deal with the complex Web Workers API.

Please upvote this Node.js issue 🙏 It would let us reduce the amount of dependencies and simplify the code.

Works in Node.js and browsers.

Install

npm install make-asynchronous

Usage

import makeAsynchronous from 'make-asynchronous';

const fn = makeAsynchronous(number => {
	return performExpensiveOperation(number);
});

console.log(await fn(2));
//=> 345342

API

makeAsynchronous(function)

Returns a wrapped version of the given function which executes asynchronously in a background thread (meaning it will not block the main thread).

The given function is serialized, so you cannot use any variables or imports from outside the function scope. You can instead pass in arguments to the function.

makeAsynchronousIterable(function)

Make the iterable returned by a function asynchronous by running it in a worker.

import {makeAsynchronousIterable} from 'make-asynchronous';

const fn = makeAsynchronousIterable(function * (number) {
	yield * performExpensiveOperation(number);
});

for await (const number of fn(2)) {
	console.log(number);
}

fn.withSignal(signal)

The function returned by makeAsynchronous and makeAsynchronousIterable has an additional method which allows an AbortSignal to be provided.

import makeAsynchronous from 'make-asynchronous';

const fn = makeAsynchronous(number => {
	return performExpensiveOperation(number);
});

const controller = new AbortController();
const timeoutId = setTimeout(() => {
	controller.abort();
}, 1000); // 1 second timeout

const result = await fn.withSignal(controller.signal)(2);
clearTimeout(timeoutId);

console.log(result);
//=> 345342

Related

• make-synchronous - Make an asynchronous function synchronous
• sleep-synchronously - Block the main thread for a given amount of time

make-asynchronous's Issues

Support iterators

iterator -> async iterator

AbortController support

AbortSignals should be accepted though they are only supported since Node.js 16. What to do for Node.js 14? Perhaps we run a loose check for AbortSignal so that third-party implementations could be used in older versions.

getting DOMException in earlier versions

Saw this and just want to suggest you about https://github.com/jimmywarting/node-domexception

make-asynchronous/index.js

Lines 20 to 25 in 8be62c9

	/**
	TODO: Remove AbortError and just throw DOMException when targeting Node 18.
	*/
	const getDOMException = errorMessage => globalThis.DOMException === undefined
	? new AbortError(errorMessage)
	: new DOMException(errorMessage);