JavaScript Object.isFrozen()

Definition and Usage

Object.isFrozen() This method is used to check if an object is frozen. If the object is frozen, it returns true.

Related methods:

Object.preventExtensions() Modification is allowed, but adding properties is prevented.

Object.seal() Allows modification but prevents addition and deletion of properties.

Object.freeze() Prevents modification, addition, and deletion of properties.

Object.isExtensible() Returns true if the object is extensible.

Object.isSealed() Returns true if the object is sealed.

Object.isFrozen() Returns true if the object is frozen.

Instance

Example 1

// Create an object
const person = {firstName: "Bill", lastName: "Gates"};
// Freeze the object
Object.freeze(person);
// This will return true
let text = Object.isFrozen(person);

Try it yourself

Example 2

const fruits = ["Banana", "Orange", "Apple", "Mango"];
Object.freeze(fruits);
// This will return true:
let answer = Object.isFrozen(fruits);

Try it yourself

Syntax

Object.isFrozen(object)

Parameter

Return value

Browser support

Object.isFrozen() Is a feature of ECMAScript5 (ES5).

Since July 2013, all modern browsers have fully supported ES5 (JavaScript 2009):