Javascript includes() or indexOf() Check If String Contains Substring

In this post, we will discuss the ways in Javascript on how to check if a string contains other substring or not.

There are multiple ways to check if a string contains substring or not, but if we’re using vanilla Javascript and not using any other library or package then we can use the following two methods:

includes()

The includes() Javascript method return boolean value as true if the substring is found else false is returned.

<script>
    var myLargeText = "I very long string to find a small string out of it quickly";
    console.log(myLargeText.includes('small')); // OUTPUT true
</script>

The only con of using includes() is, it is available on latest browsers 

If you want to use a script in order browsers then you can opt for indexOf() method.

 

indexOf()

As the name sounds, this method is actually used to find the starting index of a substring in the text string. You can use the indexOf() method as shown below to check if a string is a substring.

var myLargeText = "I very long string to find a small string out of it quickly";
 console.log(myLargeText.indexOf('small')> -1); // OUTPUT true

or you can create a reusable function as shown below 

<script>
    var myLargeText = "I very long string to find a small string out of it quickly";
    console.log(isFound(myLargeText,'small')); // OUTPUT true

    function isFound(myLargeText,substring){
        return (myLargeText.indexOf(substring)> -1);
    }
</script>