Nodejs Utililty Methods Array Set

Array.prototype.set = function () {
    var copy = this.slice();
    copy.sort()
    var result = "{" + copy[0];
    for (var i = 1; i < copy.length; i++)
        result += "," + copy[i];
    result += "}";
    return result;
};
...

Array.prototype.set = function(index, item){
  if (index >= this.length){
    this.add(index, item);
  } else {
    this[index] = item;

Array.prototype.set = function(key,value){
  this[key] = value;

Array.prototype.setArray = function (array) {
    this.length = array.length;
    for (var i = 0; i < array.length; i++) {
        this[i] = array[i];
};

Array.prototype.setItem = function(value,mode)
  var p = this.indexOf(value);
  if(mode == 0)
    mode = (p == -1) ? +1 : -1;
  if(mode == +1) {
    if(p == -1)
      this.push(value);
  } else if(mode == -1) {
...

Array.prototype.setTo = function (targetArray) {
    if (!targetArray || targetArray.length < 1)
        return false;
    if(this.length != size)
      for(var i = 0; i < size; i++)
    this.push([]);
    for (var i = 0; i < size; i++) {
        for(var j = 0; j < size; j++)
            this[i][j] = targetArray[i][j];
    return this;

Array.prototype.setWhere = function (property, value, setProperty, setValue) {
    "use strict";
    for(var i = 0; i < this.length; i++) {
        if(this[i][property] === value) {
            this[i][setProperty] = setValue;
            return;
};
...