array-includes

What is array-includes?

The array-includes npm package provides a simple utility function for checking if an array includes a certain element, with optional support for the fromIndex parameter. It is a polyfill for the Array.prototype.includes method, which is part of the ECMAScript 2016 (ES7) standard but may not be available in all environments.

What are array-includes's main functionalities?

Check if an array includes a specific element

This feature allows you to check if an array contains a specific element. It returns true if the element is found, otherwise false.

var arrayIncludes = require('array-includes');
var myArray = [1, 2, 3];
var includesTwo = arrayIncludes(myArray, 2); // true

Check if an array includes a specific element starting from a given index

This feature allows you to check if an array contains a specific element, starting the search from a given index. It is useful when you want to ignore certain elements at the beginning of the array.

var arrayIncludes = require('array-includes');
var myArray = [1, 2, 3, 2];
var includesTwoFromIndex2 = arrayIncludes(myArray, 2, 2); // true

Other packages similar to array-includes

lodash.includes

Lodash is a popular utility library that includes a method called _.includes. This method is similar to array-includes but offers additional features such as deep path string checks for objects and is part of a larger utility library.

underscore

Underscore is another utility library that provides a method called _.contains (also aliased as _.includes). It is similar to array-includes but is part of a larger set of utility functions for working with arrays, objects, and functions.

README

array-includes

An ES7/ES2016 spec-compliant Array.prototype.includes shim/polyfill/replacement that works as far down as ES3.

This package implements the es-shim API interface. It works in an ES3-supported environment and complies with the proposed spec.

Because Array.prototype.includes depends on a receiver (the this value), the main export takes the array to operate on as the first argument.

Engines that need this package include:

• IE (all versions)
• Safari < 9
• Firefox < 43, and 99-101
• Chrome < 47
• Edge < 14
• node < 6

Getting started

npm install --save array-includes

Usage

Basic usage: includes(array, value[, fromIndex=0])

var includes = require('array-includes');
var assert = require('assert');
var arr = [ 'one', 'two' ];

includes(arr, 'one'); // true
includes(arr, 'three'); // false
includes(arr, 'one', 1); // false

Example

var arr = [
	1,
	'foo',
	NaN,
	-0
];

assert.equal(arr.indexOf(0) > -1, true);
assert.equal(arr.indexOf(-0) > -1, true);
assert.equal(includes(arr, 0), true);
assert.equal(includes(arr, -0), true);

assert.equal(arr.indexOf(NaN) > -1, false);
assert.equal(includes(arr, NaN), true);

assert.equal(includes(arr, 'foo', 0), true);
assert.equal(includes(arr, 'foo', 1), true);
assert.equal(includes(arr, 'foo', 2), false);

/* when Array#includes is not present */
delete Array.prototype.includes;
var shimmedIncludes = includes.shim();

assert.equal(shimmedIncludes, includes.getPolyfill());
assert.equal(arr.includes('foo', 1), includes(arr, 'foo', 1));

/* when Array#includes is present */
var shimmedIncludes = includes.shim();

assert.equal(shimmedIncludes, Array.prototype.includes);
assert.equal(arr.includes(1, 'foo'), includes(arr, 1, 'foo'));

Tests

Simply clone the repo, npm install, and run npm test

Changelog

v3.1.9 - 2025-06-01

Commits

• [Deps] update call-bind, es-abstract, es-object-atoms, get-intrinsic, is-string 3b934ae
• [Refactor] use call-bound and math-intrinsics directly 160ea60
• [Dev Deps] update @es-shims/api, @ljharb/eslint-config, auto-changelog, hastrict-mode, tape 4e4c67d
• [Tests] replace aud with npm audit 9c5ec1c
• [Dev Deps] add missing peer dep 863d207