p-settle

Settle promises concurrently and get their fulfillment value or rejection reason

Install

npm install p-settle

Usage

import fs from 'node:fs/promises';
import pSettle from 'p-settle';

const files = [
	'a.txt',
	'b.txt' // Doesn't exist
].map(fileName => fs.readFile(fileName, 'utf8'));

console.log(await pSettle(files));
/*
[
	{
		status: 'fulfilled',
		value: '🦄',
		isFulfilled: true,
		isRejected: false,
	},
	{
		status: 'rejected',
		reason: [Error: ENOENT: no such file or directory, open 'b.txt'],
		isFulfilled: false,
		isRejected: true,
	}
]
*/

API

pSettle(array, options?)

Returns a Promise<object[]> that is fulfilled when all promises from the array argument are settled.

The objects in the array have the following properties:

• status ('fulfilled' or 'rejected', depending on how the promise resolved)
• value or reason (Depending on whether the promise fulfilled or rejected)
• isFulfilled
• isRejected

array

Type: Array<ValueType | PromiseLike<ValueType> | ((...args: any[]) => PromiseLike<ValueType>)>

The array can contain a mix of any value, promise, and async function. Promises are awaited. Async functions are executed and awaited. The concurrency option only works for elements that are async functions.

options

Type: object

concurrency

Type: number (Integer)
Default: Infinity
Minimum: 1

The number of concurrently pending promises.

Note: This only limits concurrency for elements that are async functions, not promises.

isFulfilled(object)

This is a type guard for TypeScript users.

This is useful since await pSettle(promiseArray) always returns a PromiseResult[]. This function can be used to determine whether PromiseResult is PromiseFulfilledResult or PromiseRejectedResult.

isRejected(object)

This is a type guard for TypeScript users.

This is useful since await pSettle(promiseArray) always returns a PromiseResult[]. This function can be used to determine whether PromiseResult is PromiseRejectedResult or PromiseFulfilledResult.

Related

• p-reflect - Make a promise always fulfill with its actual fulfillment value or rejection reason
• p-map - Map over promises concurrently
• More…