/delay

Delay a promise a specified amount of time

Primary LanguageJavaScriptMIT LicenseMIT

delay

Delay a promise a specified amount of time

If you target Node.js only, you can use import {setTimeout} from 'node:timers/promises'; await setTimeout(1000); instead. This package can still be useful if you need browser support or the extra features.

Install

npm install delay

Usage

import delay from 'delay';

bar();

await delay(100);

// Executed 100 milliseconds later
baz();

API

delay(milliseconds, options?) default import

Create a promise which resolves after the specified milliseconds.

rangeDelay(minimum, maximum, options?)

Create a promise which resolves after a random amount of milliseconds between minimum and maximum has passed.

Useful for tests and web scraping since they can have unpredictable performance. For example, if you have a test that asserts a method should not take longer than a certain amount of time, and then run it on a CI, it could take longer. So with this method, you could give it a threshold instead.

milliseconds

mininum

maximum

Type: number

Milliseconds to delay the promise.

options

Type: object

value

Type: unknown

A value to resolve in the returned promise.

import delay from 'delay';

const result = await delay(100, {value: '🦄'});

// Executed after 100 milliseconds
console.log(result);
//=> '🦄'
signal

Type: AbortSignal

The returned promise will be rejected with an AbortError if the signal is aborted.

import delay from 'delay';

const abortController = new AbortController();

setTimeout(() => {
	abortController.abort();
}, 500);

try {
	await delay(1000, {signal: abortController.signal});
} catch (error) {
	// 500 milliseconds later
	console.log(error.name)
	//=> 'AbortError'
}

clearDelay(delayPromise)

Clears the delay and settles the promise.

If you pass in a promise that is already cleared or a promise coming from somewhere else, it does nothing.

import delay, {clearDelay} from 'delay';

const delayedPromise = delay(1000, {value: 'Done'});

setTimeout(() => {
	clearDelay(delayedPromise);
}, 500);

// 500 milliseconds later
console.log(await delayedPromise);
//=> 'Done'

createDelay({clearTimeout, setTimeout})

Creates a new delay instance using the provided functions for clearing and setting timeouts. Useful if you're about to stub timers globally, but you still want to use delay to manage your tests.

import {createDelay} from 'delay';

const customDelay = createDelay({clearTimeout, setTimeout});

const result = await customDelay(100, {value: '🦄'});

// Executed after 100 milliseconds
console.log(result);
//=> '🦄'

Related

  • delay-cli - CLI for this module
  • p-cancelable - Create a promise that can be canceled
  • p-min-delay - Delay a promise a minimum amount of time
  • p-immediate - Returns a promise resolved in the next event loop - think setImmediate()
  • p-timeout - Timeout a promise after a specified amount of time
  • More…