JavaScript Glossary: Array .includes() Method

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Basics

This method checks if an array contains a given element. The return value for this method is a Boolean. true if the element exists in the array and false if otherwise.

[10, 20, 30, 40].includes(50)
// False

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Array.includes():

• Takes a value as an argument
• Checks the array if the value exists within the array
• Returns true or false.
• If no argument is provided, it returns false.

Syntax

array.includes(searchValue, startIndex)

2 Parameters

searchValue This is the value to search the array for.

startIndex (optional) This the position in the array at which the search begins.

Returns a boolean

The method will return an the Boolean true if the array contains the searchValue and false if it doesn’t. If no arguments are provided, false is returned by the method.

const names = ['Johnny', 'Pete', 'Sammy']
const myName = 'Pete';

const hasMyName = names.includes(myName);
console.log(hasMyName);
// output: true

Common Uses and Snippets

Checking if an array contains a certain value

The includes method is commonly used to check if an array has a certain value in it.

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