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

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

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

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