includes (Lodash Compatibility)

::: warning Use Array.prototype.includes

This includes function operates slowly due to object iteration and SameValueZero comparison processing. For arrays, JavaScript's native Array.prototype.includes method is faster and more standardized.

Instead, use the faster and more modern Array.prototype.includes.

:::

Checks if a specific value is included in an array, object, or string.

const hasValue = includes(collection, target, fromIndex);

Usage

includes(collection, target, fromIndex)

Use includes when you want to check if a specific value exists in an array, object, or string. It compares values using the SameValueZero method.

import { includes } from 'es-toolkit/compat';

// Find value in array
includes([1, 2, 3], 2);
// Returns: true

// Find in object values
includes({ a: 1, b: 'a', c: NaN }, 'a');
// Returns: true

// Find substring in string
includes('hello world', 'world');
// Returns: true

You can start searching from a specific index.

import { includes } from 'es-toolkit/compat';

// Search from index 2
includes([1, 2, 3, 2], 2, 2);
// Returns: true (found at index 3)

// Negative index counts from the end
includes([1, 2, 3], 2, -2);
// Returns: true

null or undefined always return false.

import { includes } from 'es-toolkit/compat';

includes(null, 1); // false
includes(undefined, 1); // false

You can also search for substrings in strings.

import { includes } from 'es-toolkit/compat';

// Search from beginning
includes('hello', 'e');
// Returns: true

// Search from specific position
includes('hello', 'e', 2);
// Returns: false (no 'e' after index 2)

It can correctly find NaN values.

import { includes } from 'es-toolkit/compat';

includes([1, 2, NaN], NaN);
// Returns: true

includes({ a: 1, b: NaN }, NaN);
// Returns: true

Parameters

• collection (Array | Record<string, any> | string | null | undefined): The array, object, or string to search.
• target (any): The value to find.
• fromIndex (number, optional): The index to start searching from. Negative values count from the end. Default is 0.

Returns

(boolean): Returns true if the value exists, false otherwise.