Nodejs Utililty Methods Array Select

Array.prototype.select = function (selector) {
    if (selector == null || typeof (selector) !== 'function') throw new Error('selector should');
    var result = [];
    for (var i = 0; i < this.length; i++) {
        result.push(selector(this[i]));
    return result;
};

Array.prototype.select = Array.prototype.map || function (selector, context) {
  context = context || window;
  var arr = [];
  var l = this.length;
  for (var i = 0; i < l; i++)
    arr.push(selector.call(context, this[i], i, this));
  return arr;
};

Array.prototype.select = function(transformer) {
    if (typeof(transformer) != "function") {
        throw new Error("The argument must be a function");
    var arr = [];
    for (var i = this.length - 1; i >= 0; i--) {
        arr[i] = transformer(this[i]);
    return arr;
...

let src = [
    [1, 2, 3, 4],
    [2, 7, 8, 9],
    [1, 2, 3, 4],
];
let src1 = [1, 123, 567];
Array.prototype.selectMany = function(fn) {
    let resultArray = [];
    let result = [];
...

Array.prototype.selectMany = function (selector, resSelector) {
  resSelector = resSelector || function (i, res) { return res; };
  return this.aggregate(function (a, b) {
    return a.concat(selector(b).select(function (res) { return resSelector(b, res) }));
  }, []);
};

Array.prototype.selectObjects = function(key, array){
  var toReturn = []
  $.each(this, function(i, object){
    if(array.indexOf(object[key]) > -1){
      toReturn.push(object)
  })
  return toReturn

Array.prototype.selectOne = function(filter)
  for (var i = 0; i< this.length; i++) {
    if(filter(this[i])){
      return this[i];
  return null;

var alphabet = "aabcdeefghiijklmnoopqrstuuvwxyyz";
function randint(min, max) {
    return Math.floor(Math.random() * (max - min)) + min;
Array.prototype.selectRandom = function() {
    return this[randint(0, this.length)];
};
function random_word(min, max) {
    var word = "";
...

Array.prototype.selects = function (cond) {
  var results = [];
  this.forEach(function (el) {
    if (cond(el)) {
      results.push(el);
  });
  return results