How to Check if String Contains Substring in JavaScript

When you are working with strings, you might want to know if a string contains a substring.

Maybe we need to check if a string is in the right format or contains the right characters.

Either way, in this post, we'll learn the best ways in which you can check if a string contains a substring in JavaScript.

Using includes()

The best way one can check if a string contains a substring is to utilize the includes() method.

This built-in function on the String object checks if a string contains a substring.

It takes a substring as an argument and returns a boolean value, which is exactly what we need.

Here's an example of how to use the includes() method:

JAVASCRIPT
const string = "Hello World";
const contains = string.includes("World");

console.log(contains); // true

Using indexOf()

Another way you can check if a string in JavaScript contains a substring is to utilize the indexOf() method.

This function instead returns the index of the first occurrence of the substring in the string.

From there, we can check if the index is greater than -1 because if it is, then the substring was found.

Here's how to use the indexOf() method to check if a string contains a substring:

JAVASCRIPT
const string = "Hello World";
const contains = string.indexOf("World") > -1;

console.log(contains); // true

If the string doesn't contain the substring, then the index will be -1.

Conclusion

In this post, we looked at the best ways in which you can check if a string contains a substring in JavaScript.

The first method uses the includes() method, and the second method uses the indexOf() method.

Hopefully, this post has been useful to you. Thanks for reading!

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