JavaScript in Operator
JavaScript in operator is an inbuilt operator which is used to check whether a particular property exists in an object or not. It returns a boolean value true if the specified property is in an object, otherwise, it returns false.
Syntax:
prop in object
Parameters:
- prop: This parameter holds the string or symbol that represents a property name or array index.
- object: This parameter is an Object that is to be checked whether it contains the prop.
Return value:
This method returns a boolean value. The value true is returned if the specified property is found in an object, else it returns false.
Example 1: Below is an example of the in-operator.
Javascript
function gfg() { // Illustration of in operator const array = [ 'Beginner' , 'for' , 'Beginner' ] // Output of the indexed number console.log(0 in array); // Output of the Value console.log( 'for' in array); // output of the Array property console.log( 'length' in array); } gfg(); |
Output
true false true
Example 2: This example shows the use of the in operator in Javascript.
Javascript
// Illustration of in operator const array = [ 'w3wiki' , 'Beginnerfor' , 'Beginner' , 'Beginner1' ] // Output of the indexed number console.log(0 in array) console.log(2 in array) console.log(5 in array) // Output of the Value console.log( 'for' in array) console.log( 'w3wiki' in array) // output of the Array property console.log( 'length' in array) |
Output
true true false false false true
Example 3: This example shows the use of the in operator in Javascript.
Javascript
// Illustration of in operator const object = { val1: 'w3wiki' , val2: 'Javascript' , val3: 'operator' , val4: 'in' }; console.log( 'val1' in object); delete object.val1; console.log( 'val1' in object); if ( 'val1' in object === false ) { object.val1 = 'w3wiki' ; } console.log(object.val1); |
Output
true false w3wiki
Supported Browsers:
- Google Chrome
- Firefox
- Opera
- Safari
- Edge
- Internet Explorer
We have a complete list of Javascript Operators, to check those please go through the Javascript Operators Complete Reference article.