findLast

Usage

import { findLast } from '@accelint/core';

// Find last even number
const lastEven = findLast((x: number) => x % 2 === 0)([1, 2, 3, 4, 5]);
// 4

// Partial application
const findLastNegative = findLast((x: number) => x < 0);
findLastNegative([5, -3, 10, -8]); // -8

Reference

function findLast<T>(
  predicate: (element: T, index: number) => boolean
): (arr: T[]) => T | null

Parameters

Parameter	Type	Description
`predicate`	`(element: T, index: number) => boolean`	Function called for each element from the end until it returns `true`. Receives the element and its index.

Returns

Returns a curried function that accepts an array and returns the last matching element, or null if no match is found.

Type Parameters

T - The type of elements in the array

Examples

Example: Finding last occurrence

import { findLast } from '@accelint/core';

const data = [1, 2, 3, 2, 1];
const lastTwo = findLast((x: number) => x === 2)(data);
// 2 (finds the second occurrence)

Example: Finding by complex condition

import { findLast } from '@accelint/core';

interface Order {
  id: number;
  status: 'pending' | 'completed' | 'cancelled';
  amount: number;
}

const orders: Order[] = [
  { id: 1, status: 'completed', amount: 100 },
  { id: 2, status: 'pending', amount: 50 },
  { id: 3, status: 'completed', amount: 200 }
];

const lastCompleted = findLast((o: Order) => o.status === 'completed')(orders);
// { id: 3, status: 'completed', amount: 200 }

Example: No match returns null

import { findLast } from '@accelint/core';

const numbers = [1, 3, 5, 7, 9];
const lastEven = findLast((x: number) => x % 2 === 0)(numbers);
// null

Good to know: The search starts from the end of the array and moves backward. The predicate is called only until a matching element is found, then iteration stops immediately.

find - Find the first matching element
findLastIndex - Find the index of the last matching element
filter - Find all matching elements

findLast

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