Skip to main content
Module

std/collections/find_last_index.ts

Deno standard library
denoland/deno_std
Go to Latest
File
1234567891011121314151617181920212223242526272829303132
// Copyright 2018-2021 the Deno authors. All rights reserved. MIT license.
/** * Returns the index of the last element in the given array matching the given predicate * * Example: * * ```ts * import { findLastIndex } from "./find_last_index.ts"; * import { assertEquals } from "../testing/asserts.ts"; * * const numbers = [ 4, 2, 7 ] * const lastIndexNumber = findLastIndex(numbers, it => it % 2 === 0) * * assertEquals(lastIndexNumber, 1) * ``` */export function findLastIndex<T>(  array: readonly T[],  predicate: (el: T) => boolean,): number | undefined {  for (let i = array.length - 1; i >= 0; i -= 1) {    const element = array[i];
    if (predicate(element)) {      return i;    }  }
  return undefined;}