Nodejs Utililty Methods Array First Item

Array.prototype.first = function() {
  return this[0];
};

Array.prototype.first=function(){
return this[0]
Array.prototype.last=function(){
return this[this.length-1]

Array.prototype.first = function() {
  return this[0];
Array.prototype.last = function() {
  return this.reverse()[0];

Array.prototype.first = function(){
    if(this.length > 0)
        return this[0];
    return null;
};

Array.prototype.first = function() {
  if (this[0] !== undefined)
    return this[0]
  else {
    throw new TypeError("Can't get first element of an empty array.")

"use strict";
Array.prototype.first = function  () {
  if (this.length === 0) {
    throw "Empty string doesn't have first element";
  return this[0];
};
console.log(["a", "b", 3].first());

Array.prototype.first = function () {
    return this[0];
};

var dict = { path: 24, montes:23, mike: 37, andrea: 21}
var friends = []
for (var name in dict) {
  friends.push(name + ":" + dict[name])
console.log(friends)
var dictAux = {}
dictAux.alice = 34
dictAux.bob = 4
...

Array.prototype.first = function(){
    if (this.length > 0)
        return this[0];
    else
        return [];

Array.prototype.first = function () {
    this.current = 0;
    return jQuery.extend(true, [], this[this.current]);
};
Array.prototype.last = function () {
    this.current = this.length - 1;
    return jQuery.extend(true, [], this[this.length - 1]);
};
Array.prototype.next = function () {
...