filter (Lodash Compatibility)

Use Array.prototype.filter()

This filter function operates slowly due to complex object processing, support for various condition formats, etc.

Instead, use the faster and more modern Array.prototype.filter().

Creates a new array with elements that satisfy the given condition.

const result = filter(collection, predicate);

Reference

filter(collection, predicate)

Use filter when you want to filter out only elements that satisfy a specific condition from an array or object. The condition can be specified in various formats such as a function, partial object, property-value pair, property name, etc.

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

// Using a test function
const numbers = [1, 2, 3, 4, 5];
filter(numbers, x => x % 2 === 0);
// Returns: [2, 4]

// Using a property name
const users = [
  { name: 'Alice', active: true },
  { name: 'Bob', active: false },
  { name: 'Charlie', active: true },
];
filter(users, 'active');
// Returns: [{ name: 'Alice', active: true }, { name: 'Charlie', active: true }]

// Using a partial object
filter(users, { active: true });
// Returns: [{ name: 'Alice', active: true }, { name: 'Charlie', active: true }]

// Using a property-value pair
filter(users, ['active', true]);
// Returns: [{ name: 'Alice', active: true }, { name: 'Charlie', active: true }]

It works the same way for objects, returning an array of values that satisfy the condition.

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

const scores = { math: 90, english: 75, science: 85 };
filter(scores, score => score >= 80);
// Returns: [90, 85]

null or undefined are treated as empty arrays.

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

filter(null, x => x > 0);
// Returns: []

filter(undefined, x => x > 0);
// Returns: []

Parameters

• collection (ArrayLike<T> | Record<string, unknown> | null | undefined): The array or object to filter.
• predicate (((item: T, index: number, collection: any) => unknown) | Partial<T> | [keyof T, unknown] | PropertyKey): The filtering condition. Can use a function, partial object, property-value pair, or property name.

Returns

(T[]): Returns a new array consisting of elements that satisfy the condition.