Palindrome numbers in JavaScript


We are required to write a JavaScript function that takes in a number and determines whether or not it is a palindrome number.

Palindrome numbers − A palindrome number is that number which reads the same from both left and right sides.

For example −

  • 343 is a palindrome number

  • 6789876 is a palindrome number

  • 456764 is not a palindrome number

Example

The code for this will be −

const num1 = 343;
const num2 = 6789876;
const num3 = 456764;
const isPalindrome = num => {
   let length = Math.floor(Math.log(num) / Math.log(10) +1);
   while(length > 0) {
      let last = Math.abs(num − Math.floor(num/10)*10);
      let first = Math.floor(num / Math.pow(10, length −1));
      if(first != last){
         return false;
      };
      num −= Math.pow(10, length−1) * first ;
      num = Math.floor(num/10);
      length −= 2;
   };
   return true;
};
console.log(isPalindrome(num1));
console.log(isPalindrome(num2));
console.log(isPalindrome(num3));

Output

And the output in the console will be −

true
true
false

Updated on: 21-Nov-2020

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