JavaScript (ES2026) reference · String Methods

JavaScript String includes() Method

Return true if the string contains the given text anywhere. Case-sensitive.

JavaScript (ES2026) Since ES2015

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Syntax

string.includes(searchString, position)

Parameter	Description
`searchString`	Text to look for.
`position` optional	Index to start searching from. Default: `0`

true or false.

Contains some text?Try it yourself

const msg = "Payment failed: card declined";
console.log(msg.includes("failed"), msg.includes("Failed"));

Output

true false

Case-insensitive searchTry it yourself

const q = "JAVA";
console.log("JavaScript".toLowerCase().includes(q.toLowerCase()));

Output

true

Version	Change
JavaScript ES2015	Added

string.indexOf() · Return the index of the first occurrence of some text, or -1 if it isn't found.
string.startsWith() · Return true if the string begins with the given text. Case-sensitive; an optional position starts the check later.
string.search() · Return the index of the first regular-expression match, or -1 if there is none.
array.includes() · Return true if the array contains a value, using SameValueZero equality (so it finds NaN, unlike indexOf).
JavaScript Strings · tutorial
JavaScript String Methods · tutorial