The includes() method is used to check whether an array contains a specific element.

  • Checks if an element exists in an array
  • Returns true or false
  • Uses strict equality (===)
  • Does not modify the original array

1.Syntax

array.includes(searchElement, fromIndex);
  • searchElement → value to find
  • fromIndex (optional) → index to start searching from

2.Basic Example

let fruits = ["Apple", "Banana", "Mango"];

console.log(fruits.includes("Banana")); // true
console.log(fruits.includes("Orange")); // false

3.Using fromIndex

let numbers = [1, 2, 3, 2, 1];

console.log(numbers.includes(2));      // true
console.log(numbers.includes(2, 2));   // true
console.log(numbers.includes(2, 3));   // false

4.includes() with NaN

Unlike indexOf(), includes() can detect NaN.

let arr = [1, NaN, 3];

console.log(arr.includes(NaN)); // true

5.includes() vs indexOf()

Feature includes() indexOf()
Return type Boolean Index / -1
Detects NaN Yes No
Readability Better Less clear

6.Using includes() with Objects

⚠ Objects are compared by reference, not value.

let users = [{ name: "Zaman" }];

console.log(users.includes({ name: "Zaman" })); // false

let user = users[0];
console.log(users.includes(user)); // true

7.Using includes() in Conditional Logic

let allowedPages = ["home", "profile", "settings"];

if (allowedPages.includes("profile")) {
  console.log("Access allowed");
}

Categorized in:

Javascript Array Methods,