2021-11-08
2621
#vanilla javascript
Fernando Doglio
4429
Nov 8, 2021 â‹… 9 min read

JavaScript Promises: race, all, allSettled, and then

Fernando Doglio Technical Manager at Globant. Author of books and maker of software things. Find me online at fdoglio.com.

Recent posts:

When is low-code the right choice? Here’s how to decide

Not sure if low-code is right for your next project? This guide breaks down when to use it, when to avoid it, and how to make the right call.

Popoola Temitope
Jul 11, 2025 â‹… 7 min read
Comparing AI App Builders — Firebase Studio vs. Lovable vs. Replit. LogRocket Article

Comparing AI app builders — Firebase Studio vs. Lovable vs. Replit

Compare Firebase Studio, Lovable, and Replit for AI-powered app building. Find the best tool for your project needs.

Emmanuel John
Jul 11, 2025 â‹… 7 min read
Gemini CLI tutorial — Will it replace Windsurf and Cursor?

Gemini CLI tutorial — Will it replace Windsurf and Cursor?

Discover how to use Gemini CLI, Google’s new open-source AI agent that brings Gemini directly to your terminal.

Chizaram Ken
Jul 10, 2025 â‹… 8 min read
React & TypeScript: 10 Patterns For Writing Better Code

React & TypeScript: 10 patterns for writing better code

This article explores several proven patterns for writing safer, cleaner, and more readable code in React and TypeScript.

Peter Aideloje
Jul 10, 2025 â‹… 11 min read
View all posts

3 Replies to "JavaScript Promises: race, all, allSettled, and then"

  1. Mozilla’s web documentation at https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Promise/all has an good workaround for the problem of rejection stopping Promise.all(). I have been using it without any issues so far:

    var p1 = new Promise((resolve, reject) => {
    setTimeout(() => resolve(‘p1_delayed_resolution’), 1000);
    });

    var p2 = new Promise((resolve, reject) => {
    reject(new Error(‘p2_immediate_rejection’));
    });

    Promise.all([
    p1.catch(error => { return error }),
    p2.catch(error => { return error }),
    ]).then(values => {
    console.log(values[0]) // “p1_delayed_resolution”
    console.log(values[1]) // “Error: p2_immediate_rejection”
    })

  2. Nice article, but one thing should be noted. You say:

    “By definition,Promise.all will run all your promises until one of the following conditions are met:”

    It’s not true. Promise.all doesn’t run anything. Promises are ALWAYS fired immediately, always. There are no methods to explicitly control Promise’s execution. Promise.all just listens their execution, but doesn’t do anything else.

Leave a Reply