Implement map on a Prototype......!

Tell us what’s happening:

can someone tel me what is my error here i ddint really understand this exercise too

Your code so far

// the global Array
var s = [23, 65, 98, 5];

Array.prototype.myMap = function(callback){
  var newArray = [];
  // Add your code below this line
  for(var i=0;i<s.length;i++)
  // Add your code above this line
  return newArray;


var new_s = s.myMap(function(item){
  return item * 2;

Your browser information:

User Agent is: Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/76.0.3806.1 Safari/537.36.

Link to the challenge:

What if I called your function like:

var z = [1, 2, 3, 4];
var new_z = z.myMap(function(item){
  return item * 2;


var new_Arr = [10, 20, 30, 40, 50].myMap(function(item){
  return item * 2;

You can not use s or another global variable inside your myMap method or the above two valid eamples would not work with your method. Also, if you understand how the normal map method works, you should be using the callback function inside your method in some way.

HINT: Review the following challenge which was back in the Object Oriented Programming section for how you can refer to the array upon the method is called.