Nodejs Utililty Methods Array Map

Array.prototype.map = function(  func ) {
  var len = this.length;
  if (typeof func != 'function') {
    throw new Error("argument must be function");
  };
  var res = [];
  var obj = arguments[1];
  console.log("obj" + obj)
  for (var i = 0; i < len; i++) {
...

Array.prototype.map = function( fn )
    var a = [];
    for( var i = 0; i < this.length; i++ ) {
        if( i in this ) a.push( fn( this[ i ] ) );
    return a;
};

Array.prototype.map = function(a) {
  const array = new Array(this.length)
  for (let i = 0; i < this.length; i++) array[i] = a(this[i], i, this)
  return array

Array.prototype.map = function(callback) {
  var result = [];
  for(var i = 0; i < this.length; i += 1) {
    result.push(callback.call(this[i]));
  return result;
};

Array.prototype.map = function (callback) {
    var obj = this;
    var value, mapped_value;
    var A = new Array(obj.length);
    for (var i = 0; i < obj.length; i++) {
        value = obj[i];
        mapped_value = callback.call(null, value);
        A[i] = mapped_value;
    return A;
};
var arr = [1, 2, 3];
var new_arr = arr.map(function (value) {
    return value * value;
});
console.log(new_arr);

Array.prototype.map = function(callback) {
  let res = [];
  this.forEach(el => res.push(callback(el)));
  return res;
};
let a = [1,2,3];
let b = a.map(el => el * el);
console.log(a);
console.log(b);
...

Array.prototype.map = function(callback){
  var a = 0,
    len = this.length,
    result = [];
  while(a < len){
    result.push(callback(this[a], a++, this));
  return result;
};
...

Array.prototype.map = function(callback){
    const newArr = []
    for(let i = 0; i < this.length; i += 1){
        let newValue = callback(this[i])
        newArr.push(newValue)
    return newArr
var someArray = [1,2,3,4]
...

Array.prototype.map = function(callback) {
  for(var i = 0, l = this.length; i < l; i++) {
    this[i] = callback(i, this[i]);
  return this;

Array.prototype.map = function (callback) {
  var mapped = [];
  function mutation(el) {
    mapped.push(callback(el));
  this.each(mutation);
  return mapped;
};