2021-03-26
1232
#vanilla javascript
Linda Ikechukwu
39897
Mar 26, 2021 ⋅ 4 min read

New ES2021 features you may have missed

Linda Ikechukwu Frontend developer. Writer. Community Strategist. Building web interfaces that connect products to their target users.

Recent posts:

You're doing vibe coding wrong: Here's how to do it right. A LogRocket article

You’re doing vibe coding wrong: Here’s how to do it right

Vibe coding isn’t just AI-assisted chaos. Here’s how to avoid insecure, unreadable code and turn your “vibes” into real developer productivity.

Chizaram Ken
Oct 28, 2025 ⋅ 11 min read

Exploring spec-driven development with the new GitHub Spec Kit

GitHub SpecKit brings structure to AI-assisted coding with a spec-driven workflow. Learn how to build a consistent, React-based project guided by clear specs and plans.

Emmanuel John
Oct 28, 2025 ⋅ 7 min read

The different ways to use CSS :has(), with examples

The CSS :has() pseudo-class is a powerful new feature that lets you style parents, siblings, and more – writing cleaner, more dynamic CSS with less JavaScript.

Daniel Schwarz
Oct 24, 2025 ⋅ 7 min read

Kombai AI: The AI agent built for frontend development

Kombai AI converts Figma designs into clean, responsive frontend code. It helps developers build production-ready UIs faster while keeping design accuracy and code quality intact.

Jude Miracle
Oct 23, 2025 ⋅ 7 min read
View all posts

3 Replies to "New ES2021 features you may have missed"

  1. Hi, thanks for writing this good article, I love it.

    However I want to propose a correction for Promise.all in Promise.any part, The Promise.all should be reject if any of the promise rejected and resolve if all promise resolved.

    https://developer.mozilla.org/en-
    US/docs/Web/JavaScript/Reference/Global_Objects/Promise/all

    Keep writing good stuff.

  2. “`
    const promise1 = new Promise((resolve) => setTimeout((resolve) => resolve, 300, ‘faster’);
    const promise2 = new Promise((reject) => setTimeout( (reject) =>reject, 100,”fastest”)
    const promise3 = new Promise((resolve) => setTimeout( (resolve) => resolve,700,’fast’);
    “`

    This promise code is just completely wrong, even if you fix the missing closing brackets. Your `setTimeout` calls take a `resolve => resolve` callback, but this reject is not the one from the promise, it’s an internal parameter of the callback. You might as well have passed the callback `foo => foo` , and it will have the same result.

    `promise2` even renames the “resolve” parameter as `reject`. Further adding to the wrongness.

    I believe you meant:

    “`
    const promise2 = new Promise((_, reject) => setTimeout(reject, 100,”fastest”));
    “`

Leave a Reply

Would you be interested in joining LogRocket's developer community?

Join LogRocket’s Content Advisory Board. You’ll help inform the type of content we create and get access to exclusive meetups, social accreditation, and swag.

Sign up now