p-timeout

Timeout a promise after a specified amount of time

Install

$ npm install p-timeout

Usage

const delay = require('delay');
const pTimeout = require('p-timeout');

const delayedPromise = delay(200);

pTimeout(delayedPromise, 50).then(() => 'foo');
//=> [TimeoutError: Promise timed out after 50 milliseconds]

API

pTimeout(input, milliseconds, message?, options?)

pTimeout(input, milliseconds, fallback?, options?)

Returns a decorated input that times out after milliseconds time.

If you pass in a cancelable promise, specifically a promise with a .cancel() method, that method will be called when the pTimeout promise times out.

input

Type: Promise

Promise to decorate.

milliseconds

Type: number

Milliseconds before timing out.

Passing Infinity will cause it to never time out.

message

Type: string | Error
Default: 'Promise timed out after 50 milliseconds'

Specify a custom error message or error.

If you do a custom error, it's recommended to sub-class pTimeout.TimeoutError.

fallback

Type: Function

Do something other than rejecting with an error on timeout.

You could for example retry:

const delay = require('delay');
const pTimeout = require('p-timeout');

const delayedPromise = () => delay(200);

pTimeout(delayedPromise(), 50, () => {
	return pTimeout(delayedPromise(), 300);
});

options

Type: object

customTimers

Type: object with function properties setTimeout and clearTimeout

Custom implementations for the setTimeout and clearTimeout functions.

Useful for testing purposes, in particular to work around sinon.useFakeTimers().

Example:

const pTimeout = require('p-timeout');
const sinon = require('sinon');

(async () => {
	const originalSetTimeout = setTimeout;
	const originalClearTimeout = clearTimeout;

	sinon.useFakeTimers();

	// Use `pTimeout` without being affected by `sinon.useFakeTimers()`:
	await pTimeout(doSomething(), 2000, undefined, {
		customTimers: {
			setTimeout: originalSetTimeout,
			clearTimeout: originalClearTimeout
		}
	});
})();

pTimeout.TimeoutError

Exposed for instance checking and sub-classing.

Related

• delay - Delay a promise a specified amount of time
• p-min-delay - Delay a promise a minimum amount of time
• p-retry - Retry a promise-returning function
• More…