JavaScript | Object.isExtensible() Method
The Object.preventExtensions() method in JavaScript is standard built-in objects which checks whether an object is extensible or not.
Syntax:
Object.isExtensible( obj )
Parameters: This method accepts single parameter as mentioned above and described below:
- obj: This parameter holds the object which which should be checked for extensiblity.
Return value: This method returns a Boolean value indicating if the given object is extensible or not.
Below examples illustrate the Object.isExtensible() Method in JavaScript:
Example 1:
javascript
const geeks1 = {};console.log(Object.isExtensible(geeks1));Object.preventExtensions(geeks1);console.log(Object.isExtensible(geeks1));const geeks2 = {}; Object.preventExtensions(geeks2); console.log( Object.isExtensible(geeks2) ); |
Output:
true false false
Example 2:
javascript
var geeks1 = {};document.writeln(Object.isExtensible(geeks1));document.writeln("<br>");document.writeln(Object.preventExtensions(geeks1));document.writeln("<br>");document.writeln(Object.isExtensible(geeks1));document.writeln("<br>");var geeks2 = Object.seal({});document.writeln(Object.isExtensible(geeks2));document.writeln("<br>");var geeks3 = Object.freeze({});document.writeln(Object.isExtensible(geeks3)); |
Output:
true [object Object] false false false
Supported Browsers: The browsers supported by Object.isExtensible() method are listed below:
- Google Chrome 6 and above
- Edge 12 and above
- Firefox 4 and above
- Internet Explorer 9
- Opera 12 and above
- Safari 5.1 and above
