Problem

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.

Example 1:

Input: arr = [1,2,3], fn = function plusone(n) { return n + 1; } Output: [2,3,4] Explanation: const newArray = map(arr, plusone); // [2,3,4] The function increases each value in the array by one.

Example 2:

Input: arr = [1,2,3], fn = function plusI(n, i) { return n + i; } Output: [1,3,5] Explanation: The function increases each value by the index it resides in.

Example 3:

Input: arr = [10,20,30], fn = function constant() { return 42; } Output: [42,42,42] Explanation: The function always returns 42.

Constraints:

0 <= arr.length <= 1000 -109 <= arr[i] <= 109 fn returns a number

Pre analysis

Inbuilt function .map isnt allowed. But specification of .map should be followed. So resultant array will be of same size as original array.