Find Index

easycodingJavaScriptArraysFunctions~10 min

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Overview

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

Examples

findIndex([1,2,3,4], x => x > 2); // 2
findIndex([1,2], x => x > 5); // -1

Solution

Reveal solution

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

find-index.js

Find Index

easycodingJavaScriptArrays

Overview

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

Examples

findIndex([1,2,3,4], x => x > 2); // 2
findIndex([1,2], x => x > 5); // -1

Solution

Reveal solution

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

NameTopicDifficulty

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