findLast (Lodash Compatibility)

Use Array.prototype.findLast

This findLast function is complex and slow due to handling various types and special conditions.

Use the faster and more modern Array.prototype.findLast instead.

Finds the last element in an array or object that satisfies a condition.

const lastEven = findLast(array, predicate);

Reference

findLast(collection, predicate?, fromIndex?)

Finds the last element in an array or object that satisfies the given condition. Searches in reverse order from the end of the array and returns the first element that satisfies the condition.

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

// Specify condition with a function
const users = [
  { user: 'barney', age: 36 },
  { user: 'fred', age: 40 },
  { user: 'pebbles', age: 18 },
];
findLast(users, o => o.age < 40);
// => { user: 'pebbles', age: 18 }

// Specify condition with an object
findLast(users, { age: 36 });
// => { user: 'barney', age: 36 }

// Specify condition with a key-value pair
findLast(users, ['age', 18]);
// => { user: 'pebbles', age: 18 }

// Specify condition with a property name (last element with truthy value)
findLast(users, 'age');
// => { user: 'fred', age: 40 }

You can also specify a starting index for the search.

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

const numbers = [1, 2, 3, 4, 5, 4, 3, 2, 1];
findLast(numbers, n => n > 3, 6); // Search in reverse from index 6
// => 4

null or undefined returns empty results.

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

findLast(null, x => x > 0); // undefined
findLast(undefined, x => x > 0); // undefined

Parameters

• collection (ArrayLike<T> | Record<string, T> | null | undefined): The array or object to search.
• predicate (ListIterateeCustom<T, boolean>, optional): The condition to apply to each element. Can be a function, object, key-value pair, or property name. Default is the identity function.
• fromIndex (number, optional): The index to start the search from. If negative, it's calculated from the end. Default is the last index of the array.

Returns

(T | undefined): Returns the last element that satisfies the condition. Returns undefined if no element satisfies the condition.