Nodejs Utililty Methods Array Index

var os = require('os');
Array.prototype.indexOf = function(obj) {
  for (var i = 0; i < this.length; i++) {
    if (this[i] == obj)
      return i;
  return -1;
Array.prototype.has = function(obj) {
...

Array.prototype.indexOf=function(obj){
  var result=-1;
  for (var i=0;i<this.length;i++){
    if (this[i]==obj){
      result=i;
      break;
  return result;
...

if(!Array.indexOf){ 
  Array.prototype.indexOf = function(obj){
    for(var i=0; i<this.length; i++){
      if(this[i]==obj){
        return i;
    return -1;

Array.prototype.indexOf = function(obj) {
  for (var i = 0; i < this.length; i++) {
    if (obj == this[i])
      return i;
  return -1;
};

if (!Array.prototype.indexOf) {
    Array.prototype.indexOf = function (obj, fromIndex) {
        if (fromIndex == null) {
            fromIndex = 0;
        } else if (fromIndex < 0) {
            fromIndex = Math.max(0, this.length + fromIndex);
        for (var i = fromIndex, j = this.length; i < j; i++) {
            if (this[i] === obj) return i;
...

Array.prototype.indexOf = function (obj, fromIndex) {
    for (var i = (fromIndex || 0); i < this.length; i++) {
        if (this[i] === obj) {
            return i;
    return -1;
};

Array.prototype.indexOf = function(obj, start) {
     for (var i = (start || 0), j = this.length; i < j; i++) {
         if (this[i] === obj) { return i; }
     return -1;
};

Array.prototype.indexOf = function(obj, start) {
     for (var i = (start || 0), j = this.length; i < j; i++) {
         if (this[i] === obj) { return i; }
     return -1;

'use strict';
Array.prototype.indexOf = function(obj, start) {
   for (var i = (start || 0), j = this.length; i < j; i++) {
       if (this[i] === obj) { 
           return i; 
   return -1;

Array.prototype.indexOf = function(object) {
  for (var i = 0, length = this.length; i < length; i++)
    if (this[i] == object) return i;
  return -1;
};