Nodejs String Palindrome Check isPalindrome()

Method Source Code

String.prototype.isPalindrome = function () {
  // Note that a primitive JavaScript string is not === to a String object.
  // The valueOf function returns the underlying primitive.
  return this.valueOf() === this.reverse().valueOf();
};
String.prototype.reverse = function () {
  return Array.prototype.slice.apply(this).reverse().join('');
};

let result = 0;/*from w w w . ja  va  2 s .  com*/
for (let i = 999; i > 0; i--) {
  for (let j = i; j > 0; j--) {
    let x = i * j;
    if (x.toString().isPalindrome() && x > result)
      result = x;
  }
}
print(result);

Related

1. palindrome(str)

   String.prototype.reverse = function(){ return this.split("").reverse().join(""); }
   function palindrome(str) { return str == str.reverse(); }
   console.log(palindrome("ingirumimusnocteetconsumimurigni"));
   

2. isPalindrome()

   String.prototype.isPalindrome = function() {
     var str = this;
     var half = parseInt(str.length / 2, 10);
     for (var i = 0, last = str.length - 1; i < half; ++i) {
       if (str[i] != str[last - i]) return false;
     return true;
   };
   

3. isPalindrome()

   String.prototype.isPalindrome=function(){
     var palavra=this;
     for(var i=0;i<palavra.length/2;i++){
       if(palavra[i]!=palavra[palavra.length-1-i]){
         return false;
     return true;
   

4. isPalindrome()

   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();  
   ...
   

5. 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;
   ...
   

6. isPalindrome()

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

7. isPalindrome()

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

8. isPalindrome()

   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('');
   

9. isPalindrome()

   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;