How to check if a string contains a substring in JavaScript?

In this tutorial, I am going to show you a very simple, fast, and modern(ES6) way to check whether a string contains a substring in JavaScript.

String.prototype.includes() method checks if one string may be found within another string. It returns a boolean value of true if the string is found, otherwise false.

Old way: Before ES6, String.prototype.indexOf() method was used to check whether a string contains a substring, which returns -1 when a substring cannot be found.

Let’s say you following string

let title = '12 Ways to Tell Someone Is Really Intelligent'

To check whether variable title contains string Intelligent, we can use String.prototype.includes() as follows

let title = '12 Ways to Tell Someone Is Really Intelligent'
let textIsPresent = title.includes('Intelligent')

Now, if you console.log the textIsPresent variable, you should get the output as true

let title = '12 Ways to Tell Someone Is Really Intelligent'
let textIsPresent = title.includes('Intelligent')

console.log(textIsPresent) // Output: true

The includes() method is case sensitive i.e. it would return false if you check the inclusion of string intelligent in title string.