JavaScript in Operator
Improve
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 = ['geeks', 'for', 'geeks'] // 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 operatorconst array = ['geeksforgeeks', 'geeksfor', 'geeks', 'geeks1']// Output of the indexed numberconsole.log(0 in array)console.log(2 in array)console.log(5 in array)// Output of the Valueconsole.log('for' in array)console.log('geeksforgeeks' in array)// output of the Array propertyconsole.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 operatorconst object = { val1: 'Geeksforgeeks', 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 = 'GEEKSFORGEEKS';}console.log(object.val1); |
Output
true false GEEKSFORGEEKS
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.
Share your thoughts in the comments
