Skip to content

The Object isExtensible() method

Find out all about the JavaScript isExtensible() method of the Object object

THE AHA STACK MASTERCLASS

Now open with 50% off launch discount!

This method checks if we can add new properties to an object.

Any object is extensible, unless it’s been used as an argument to

Usage:

const dog = {}
Object.isExtensible(dog) //true
const cat = {}
Object.freeze(cat)
Object.isExtensible(cat) //false
→ Get my JavaScript Beginner's Handbook

I wrote 20 books to help you become a better developer:

  • Astro Handbook
  • HTML Handbook
  • Next.js Pages Router Handbook
  • Alpine.js Handbook
  • HTMX Handbook
  • TypeScript Handbook
  • React Handbook
  • SQL Handbook
  • Git Cheat Sheet
  • Laravel Handbook
  • Express Handbook
  • Swift Handbook
  • Go Handbook
  • PHP Handbook
  • Python Handbook
  • Linux Commands Handbook
  • C Handbook
  • JavaScript Handbook
  • CSS Handbook
  • Node.js Handbook
...download them all now!

Related posts that talk about js: