Array Mappings.js

/*
Description:
Array Mappings
Oh no, the map method for arrays has been disabled. Can you fix it?

In case you haven't come across the map method for arrays, here is how it works:

[1,2,3].map(x => x ** 2) === [1,4,9]
[1,2,3].map(x => 2 * x) === [2,4,6]
[1,2,3].map(x => 2 ** x) === [2,4,8]
[1,2,3].map(x => x.toString()) === ["1","2","3"]
["1","2","3"].map(x => parseInt(x)) === [1,2,3]
["random","array","to","be","mapped"].map(x => mapping(x)) === [mapping("random"),mapping("array"),mapping("to"),mapping("be"),mapping("mapped")]
The map method does not mutate the original array.
*/
 Array.prototype.map = function(callback/*, thisArg*/) {

    var T, A, k;

    if (this == null) {
      throw new TypeError('this is null or not defined');}
    var O = Object(this);
    var len = O.length >>> 0;
    if (typeof callback !== 'function') {
      throw new TypeError(callback + ' is not a function');}
    if (arguments.length > 1) {
      T = arguments[1];}
    A = new Array(len);
    k = 0;
    while (k < len) {
      var kValue, mappedValue;
      if (k in O) {
        kValue = O[k];
        mappedValue = callback.call(T, kValue, k, O);
        A[k] = mappedValue;
      }
      k++;
    }
    return A;
  };