LeetCode 9. Palindrome Number (javascript)

Given an integer x, return true if x is palindrome integer.

An integer is a palindrome when it reads the same backward as forward. For example, 121 is palindrome while 123 is not.

Example 1:

Input: x = 121
Output: true

Example 2:

Input: x = -121
Output: false
Explanation: From left to right, it reads -121. From right to left, it becomes 121-. Therefore it is not a palindrome.

Example 3:

Input: x = 10
Output: false
Explanation: Reads 01 from right to left. Therefore it is not a palindrome.

Example 4:

Input: x = -101
Output: false

Constraints:

• -231 <= x <= 231 - 1

Solution:

/**
 * @param {number} x
 * @return {boolean}
 */
var isPalindrome = function(x) {
    // negative number is not a Palindrome Number
    if (x < 0) return false;
    let y = x;
    let reverse = 0;
    while (y > 0) {
        let lastDigit = y % 10;
        reverse = reverse * 10 + lastDigit;
        y = parseInt(y / 10);
    }
    return reverse === x ;
};