Nodejs Utililty Methods Number Type Check

Number.prototype.isInt = function() {
  return parseFloat(this) == parseInt(this, 10) && !isNaN(this);
};

Number.prototype.isInteger = function () {
    "use strict";
    var ans = false;
    if (this % 1 == 0) {
        ans = true;
    return ans;
};

Number.prototype.isInteger = function(){
  var ans = false;
  if(this%1==0){
    ans = true;
  return ans;
};

Number.prototype.isInteger = function(){
  var ans = false;
  if(this % 1 == 0){
    ans = true
  return ans;

var assert=require('assert');
var Number=function(number){
    this.number = number;
Number.prototype.isNumber=function(){
    return isNaN(this.number);
Number.prototype.isEven=function(){
    return this.number%2==0;
...

Number.prototype.isNumber = function()
  try
    var value = this.toString();
    value = value.replace(",","");
      if (parseFloat(value)!= value)
        return false;
      else
...

function isNumber(input) {
    return typeof input === "number" ? true : false;

function isNumber(n) {
   return typeof n == 'number';

function isNumber(n) 
  return !isNaN(parseFloat(n)) && isFinite(n);

function isNumber(value){
  var text = /^[0-9]*$/;
  return text.test(value);