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

Readme

Source

#array-includes

A spec-compliant Array.prototype.includes shim/polyfill/replacement that works as far down as ES3. Invoke its "shim" method to shim Array.prototype.includes if it is unavailable.

Example

var includes = require('array-includes');
var assert = require('assert');
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), false);
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);

var includes = require('array-includes');
var assert = require('assert');
/* when Array#includes is not present */
delete Array.prototype.includes;
var shimmedIncludes = includes.shim();
assert.equal(shimmedIncludes, includes);
assert.deepEqual(arr.includes('foo', 1), includes(arr, 'foo', 1));

var includes = require('array-includes');
var assert = require('assert');
/* when Array#includes is present */
var shimmedIncludes = includes.shim();
assert.notEqual(shimmedIncludes, includes);
assert.equal(shimmedIncludes, Array.prototype.includes);
assert.deepEqual(arr.includes(1, 'foo'), includes(arr, 1, 'foo'));

Tests

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

Keywords

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Last updated on 07 Jan 2015

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