JavaScript : Check If String Contains Substring -

In this tutorial, you’ll see a couple of ways to check if string contains substring using JavaScript.

Other tutorials in JavaScript Array series.

Using indexOf

You can use the String.indexOf method to find a substring in a string. indexOf methods returns a index greater than 0 if the substring is present in the string. If the substring is not found it will return -1.

Here is a code which demonstrate the same :

    var position = 'codehandbook'.indexOf('hand')
    console.log('substring starts at index ', position)

The above code will display the following output:

    // output
    "substring starts at index " 4

So if indexOf method returns -1 the substring is not found and if it returns a value greater than -1 the substring is found.

Using RegExp

You can use regular expressions to check if a string contains substring. For this to work you need to create a regular expression using your search string and test it against the main string. Here is the JavaScript code which shows the same :

    var mainString = 'codehandbook'
    var substr = /hand/
    var found = substr.test(mainString)
    if(found){
      console.log('Substring found !!')
    } else {
      console.log('Substring not found !!')
    }

As seen in the above code, you have converted the search term into a regular expression and used the test method to test if the substring if found.

Using Includes

You can check if a string contains substring using the includes method. It returns true if the substring is found and false if the substring is not found. Here is a JavaScript code sample :

    var found = 'codehandbook'.includes('hand')
    if(found){
      console.log('Substring found !!')
    } else {
      console.log('Subtring not found !!')
    }

The above code will have the following output :

    // output
    "Substring found !!"

Wrapping It Up

In this tutorial, you learnt different methods to check if a string contains substring. Have you used any other approach for finding the substring ? Do let us know your thoughts in the comments below.