Nodejs Utililty Methods String Palindrome Check

String.prototype.isPalindrome = function() {
  var val = this.toString().toLowerCase();
  var reverse = val.split('').reverse().join('');
  return val === reverse;
var str = 'something';
var result = str.isPalindrome();  
var str2 = 'level';
var result2 = str2.isPalindrome();  
...

'use strict';
String.prototype.isPalindrome = String.prototype.isPalindrome || function () {
  let length = Math.floor(this.length / 2);
  for (let i = 0; i < length; i++) {
    if (this[i] !== this[this.length - i - 1]) {
      return false;
  return true;
...

String.prototype.isPalindrome = function () {
  return this.valueOf() === this.reverse().valueOf();
};
String.prototype.reverse = function () {
  return Array.prototype.slice.apply(this).reverse().join('');
};
let result = 0;
for (let i = 999; i > 0; i--) {
  for (let j = i; j > 0; j--) {
...

var first = 999,
    second = 999,
    largestPalindromicProduct = 0;
String.prototype.isPalindrome = function() {
  return this == this.reverse();
while(first > 99) {
  second = first;
  while(second > 99) {
...

var isPalindrome = function(str){
  var i = 0;
  var j = str.length-1;
  while (i <= j){
    if (str[i] != str[j]){
      return false;
    i++;
    j--;
...

String.prototype.isPalindrome = ()=>{
  return this.replace(/[^a-zA-Z ]/g, "").replace(/ /g,'').trim().toLowerCase() == this.replace(/[^a-zA-Z ]/g, "").replace(/ /g,'').trim().toLowerCase().split('').reverse().join('');

var isPalindrome = function(inString) {
  var inString = inString.toLowerCase();
  for (var i = 0, j = inString.length-1; i < inString.length/2; i++, j--) {
    if (inString[i] != inString[j]){
      return false;
  return true;
String.prototype.isPalindrome = function isPalindrome() {
  console.log(this);
  var new_str = this.toString().replace(" ", "");
  if (new_str == new_str.split("").reverse().join("")) {
    return true;
  } else {
    return false;