Nodejs Utililty Methods Array Map

Array.prototype.map = function (transform) {
  let mappedArray = [];
  const len = this.length;
  for (let i = 0; i < len; i += 1) {
    mappedArray.push(transform(this[i], i, this));
  return mappedArray;
};

Array.prototype.map = function(transformer) {
  var result = []
  for ( var i = 0; i < this.length; i++) {
    result.push(transformer(this[i]));
  return result;

const stocks= [
  {symbol: 'XFX', price: 240.22, volume: 23432},
  {symbol: 'TNZ', price: 332.19, volume: 234},
  {symbol: 'JXJ', price: 120.22, volume: 5323},
]
Array.prototype.map2= function(projection) {
  let results= []
  this.forEach(item => results.push(projection(item)))
  return results
...

Array.prototype.mapByTwo = function(fun ) {
  if (typeof fun != "function")
    throw new TypeError();
  var len = this.length >>> 0;
  var thisp = arguments[1];
  var k = 0;
  var A = new Array(Math.ceil(len/2));
  if (len/2 < A.length) {
    this.push(null);
...

Array.prototype.mapMe = function (func) {
  var arr = this, result = [];
  for (var i = 0; i < arr.length; i++) {
    result.push(func(arr[i]));
  return result;
};

Array.prototype.mapValues = function(value) { 
    return this.map(function(e) { 
        return e[value] 
    })

Array.prototype.mapp = function(callback) {
  var newArray = [];
  for(var i = 0; i < this.length; i++){
    newArray.push(callback(this[i]));
  return newArray;
var x = [1,2,3];
x.mapp(function(ele) {
...

Array.prototype.mapper = function(callback){
    var arr = [];
    for (var i = 0; i < this.length; i++)
        callback(this[i]);
    return arr;
};
var arr = [1, 2, 3];
Array.prototype.mapper = function(callback){
    for (var i = 0; i < this.length; i++)
...

Array.prototype.mapx=function(f,t){
  var b=this.length,a=new Array(b);
  for(var i=0;i<b;i++){
    a[i]=f.call(t,this[i],i,this);
  return a;