includes in JavaScript- How to use it?

includes in JavaScript- How to use it?

Hey readers, in this article we will be discussing how to use the includes method in JavaScript in a step-wise, efficient manner. If you are a beginner and want to learn JavaScript then do check out the course on Codedamn.


JavaScript is one of the most used languages when it comes to building web applications as it allows developers to wrap HTML and CSS code in it to make web apps interactive. It allows a web application to be interactive. It is also used for making animations on websites and has a large community on GitHub. JavaScript has tons of libraries, one of which is React which we will be covering in this article later. 

Use cases: 

  • Building web server and its interactive functions
  • Animations and graphics, adding special effects to web components
  • Validating forms and exception errors
  • Adding behavior and functionalities to web pages

Since JavaScript is a scripting language, it works without any libraries. Developers are free to write JavaScript language code anywhere and can still run it in the browser. There is no structure in JavaScript, the browser executes each line of the code from top to down.

Introduction to includes method in JavaScript

The includes() method in JavaScript determines whether or not a string contains the specified characters. If the string contains the characters, this function returns true; otherwise, it returns false.

Note that the includes() method is case sensitive, which means that Uppercase and Lowercase characters are treated differently.


string.includes(searchvalue, start)

Parameters that were used:

The string in which the search will take place is called the search value.

start: This is where the search will begin to be processed (although this parameter is not necessary if this is not mentioned the search will begin from the start of the string).

Returns either a Boolean true or false indicating the presence or absence of something.

Input : Welcome to Codedamn.


Output : true

Explanation: Because the second argument isn’t set, the search will begin at the beginning index. And it will look for the word Geeks in the string, and if it is found, it will return true.

Input: Welcome to Codedamn.


Output: false

Explanation: Because the second argument is not defined in this situation, the search will begin from the beginning index. However, because this function is case-sensitive, the two texts will be treated differently, resulting in a boolean false.

Because it’s case-sensitive.

If an array contains a specified value, the includes() function returns true.

If the value cannot be retrieved, the includes() method returns false.

The case is important when using the includes() function.


array.includes(element, start)

Element- Required.

The value to search for.

Start- Optional.

Start position. Default is 0.

Return value


This was about the includes method in JavaSript using HTML, if you want to learn more about javascript, do check out the article and course on Codedamn of javascript along with the course. Hope you liked this, if you have any queries or suggestions do let us know in the comments. 

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