#2635 - Apply Transform Over Each Element in Array

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Problem Description

Given an integer array arr and a mapping function fn, return a new array with a transformation applied to each element.

The returned array should be created such that returnedArray[i] = fn(arr[i], i).

Please solve it without the built-in Array.map method.

Solution

/**
 * @param {number[]} arr
 * @param {Function} fn
 * @return {number[]}
 */
var map = function(arr, fn) {
  const result = [];

  for (let i = 0; i < arr.length; i++) {
    result.push(fn(arr[i], i));
  }

  return result;
};