Find Last Index

easycodingJavaScriptArraysFunctions~10 min

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Overview

Implement findLastIndex(array, predicate) — returns the index of the last match, or -1.

Examples

findLastIndex([1,2,3,4], x => x > 2); // 3

Solution

Reveal solution

function findLastIndex(array, predicate) {
  for (let i = array.length - 1; i >= 0; i--) {
    if (predicate(array[i], i, array)) return i;
  }
  return -1;
}

find-last-index.js

Find Last Index

easycodingJavaScriptArrays

Overview

Implement findLastIndex(array, predicate) — returns the index of the last match, or -1.

Examples

findLastIndex([1,2,3,4], x => x > 2); // 3

Solution

Reveal solution

function findLastIndex(array, predicate) {
  for (let i = array.length - 1; i >= 0; i--) {
    if (predicate(array[i], i, array)) return i;
  }
  return -1;
}

NameTopicDifficulty

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