p-any

What is p-any?

The p-any package is a utility for handling multiple promises in JavaScript. It returns a promise that is fulfilled when any of the input promises are fulfilled, or rejected if all of the input promises are rejected.

What are p-any's main functionalities?

Basic Usage

This feature demonstrates the basic usage of p-any. It takes an array of promises and returns a promise that resolves as soon as the first promise in the array resolves.

const pAny = require('p-any');
const promise1 = Promise.resolve('First');
const promise2 = new Promise((resolve) => setTimeout(resolve, 100, 'Second'));
const promise3 = new Promise((resolve, reject) => setTimeout(reject, 50, 'Third'));

pAny([promise1, promise2, promise3]).then(value => {
  console.log(value); // 'First'
});

Handling Rejections

This feature demonstrates how p-any handles rejections. If all input promises are rejected, p-any returns an AggregateError.

const pAny = require('p-any');
const promise1 = new Promise((resolve, reject) => setTimeout(reject, 100, 'First'));
const promise2 = new Promise((resolve, reject) => setTimeout(reject, 200, 'Second'));
const promise3 = new Promise((resolve, reject) => setTimeout(reject, 300, 'Third'));

pAny([promise1, promise2, promise3]).catch(error => {
  console.log(error); // AggregateError: All promises were rejected
});

Other packages similar to p-any

promise-any

The promise-any package provides similar functionality to p-any. It also returns a promise that resolves as soon as any of the input promises resolve, or rejects if all input promises are rejected. The main difference is that promise-any is a polyfill for the Promise.any method introduced in ES2021.

bluebird

Bluebird is a fully-featured promise library that includes a method called Bluebird.any, which provides similar functionality to p-any. Bluebird offers additional features and optimizations for working with promises, making it a more comprehensive solution for promise management.

README

p-any

Wait for any promise to be fulfilled

Useful when you need the fastest promise.

You probably want this instead of Promise.race(). Reason.

With Node.js 15, there's now a built-in Promise#any method. The benefit of this package is that it has cancellation functionality.

Install

$ npm install p-any

Usage

Checks 3 websites and logs the fastest.

import pAny from 'p-any';
import got from 'got';

const first = await pAny([
	got.head('https://github.com').then(() => 'github'),
	got.head('https://google.com').then(() => 'google'),
	got.head('https://twitter.com').then(() => 'twitter'),
]);

console.log(first);
//=> 'google'

API

pAny(input, options?)

Returns a cancelable Promise that is fulfilled when any promise from input is fulfilled. If all the input promises reject, it will reject with an AggregateError error.

input

Type: Iterable<Promise | unknown>

options

Type: object

filter

Type: Function

Receives the value resolved by the promise. Used to filter out values that doesn't satisfy a condition.

AggregateError

Exposed for instance checking.

Related

• p-some - Wait for a specified number of promises to be fulfilled
• p-locate - Get the first fulfilled promise that satisfies the provided testing function
• More…