p-timeout
Advanced tools
Package description
The p-timeout package is a utility that allows you to wrap a Promise with a timeout, after which a specified exception is thrown if the promise does not resolve or reject before the timeout period elapses. This is useful for ensuring that your application can handle situations where a Promise might take too long to complete, or when you want to enforce a strict timing policy for certain operations.
Timeout a Promise
This feature allows you to set a timeout for a Promise. If the Promise does not resolve or reject within the specified time, it will be rejected with a TimeoutError.
const pTimeout = require('p-timeout');
const doSomething = () => new Promise(resolve => setTimeout(resolve, 2000));
pTimeout(doSomething(), 1000).then(() => console.log('Resolved')).catch(error => console.log('Timed out:', error.message));Custom Timeout Error
This feature allows you to specify a custom error message for the timeout. If the Promise times out, it will be rejected with a TimeoutError that contains your custom message.
const pTimeout = require('p-timeout');
const TimeoutError = pTimeout.TimeoutError;
const doSomething = () => new Promise(resolve => setTimeout(resolve, 2000));
pTimeout(doSomething(), 1000, 'Operation timed out').then(() => console.log('Resolved')).catch(error => {
if (error instanceof TimeoutError) {
console.log('Custom timeout message:', error.message);
}
});Clearing the Timeout
This feature allows you to clear the timeout before it occurs. This is useful if the conditions of your operation change and you no longer require the timeout.
const pTimeout = require('p-timeout');
const doSomething = () => new Promise(resolve => setTimeout(resolve, 2000));
const promiseWithTimeout = pTimeout(doSomething(), 1000);
promiseWithTimeout.then(() => console.log('Resolved')).catch(error => console.log('Timed out:', error.message));
// Later, if you decide you no longer want the timeout:
pTimeout.clear(promiseWithTimeout);The promise-timeout package offers similar functionality to p-timeout, allowing you to add a timeout to a Promise. It differs in API design and error handling specifics.
Bluebird is a full-featured Promise library that includes a .timeout() method for timing out promises. It is more comprehensive than p-timeout but also larger in size and scope.
The async-timeout package is similar to p-timeout but is designed specifically for use with async functions and the async/await syntax.
Readme
Timeout a promise after a specified amount of time
npm install p-timeout
import {setTimeout} from 'node:timers/promises';
import pTimeout from 'p-timeout';
const delayedPromise = setTimeout(200);
await pTimeout(delayedPromise, {
milliseconds: 50,
});
//=> [TimeoutError: Promise timed out after 50 milliseconds]
Returns a decorated input that times out after milliseconds time. It has a .clear() method that clears the timeout.
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.
Type: Promise
Promise to decorate.
Type: object
Type: number
Milliseconds before timing out.
Passing Infinity will cause it to never time out.
Type: string | Error | false
Default: 'Promise timed out after 50 milliseconds'
Specify a custom error message or error to throw when it times out:
message: 'too slow' will throw TimeoutError('too slow')message: new MyCustomError('it’s over 9000') will throw the same error instancemessage: false will make the promise resolve with undefined instead of rejectingIf you do a custom error, it's recommended to sub-class TimeoutError:
import {TimeoutError} from 'p-timeout';
class MyCustomError extends TimeoutError {
name = "MyCustomError";
}
Type: Function
Do something other than rejecting with an error on timeout.
You could for example retry:
import {setTimeout} from 'node:timers/promises';
import pTimeout from 'p-timeout';
const delayedPromise = () => setTimeout(200);
await pTimeout(delayedPromise(), {
milliseconds: 50,
fallback: () => {
return pTimeout(delayedPromise(), {milliseconds: 300});
},
});
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:
import {setTimeout} from 'node:timers/promises';
import pTimeout from 'p-timeout';
const originalSetTimeout = setTimeout;
const originalClearTimeout = clearTimeout;
sinon.useFakeTimers();
// Use `pTimeout` without being affected by `sinon.useFakeTimers()`:
await pTimeout(doSomething(), {
milliseconds: 2000,
customTimers: {
setTimeout: originalSetTimeout,
clearTimeout: originalClearTimeout
}
});
Type: AbortSignal
You can abort the promise using AbortController.
Requires Node.js 16 or later.
import pTimeout from 'p-timeout';
import delay from 'delay';
const delayedPromise = delay(3000);
const abortController = new AbortController();
setTimeout(() => {
abortController.abort();
}, 100);
await pTimeout(delayedPromise, {
milliseconds: 2000,
signal: abortController.signal
});
Exposed for instance checking and sub-classing.
FAQs
Timeout a promise after a specified amount of time
The npm package p-timeout receives a total of 10,219,182 weekly downloads. As such, p-timeout popularity was classified as popular.
We found that p-timeout demonstrated a healthy version release cadence and project activity because the last version was released less than a year ago. It has 1 open source maintainer collaborating on the project.
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