Check if a number is a palindrome using JavaScript

A number is a palindrome if its reversion is equal to the original number:

For example:

terminal
121 is a palindrome
123 is not

3112113 is a palindrome
3112114 is not

-121 is not a palindrome, because if you revert it, you get 121-

In JavaScript you can find if a number is a palindrome as follows:

javascript
const isPalindrome = n => {
    
    return n.toString() === n.toString().split('').reverse().join('') 

}

But what if you couldn't transform the number into a string?

javascript
const isPalindrome = n => {

    let x = n, y = 0

    // E.g. n = 125
    // 1. x = 12 y = 5
    // 2. x = 1  y = 52
    // 3. x = 0  y = 521
    while(x > 0){

        y = (y * 10) + 10 * (x/10 % 1).toFixed(2)
        x = Math.floor(x/10)

    }

    return n === y

}

Optional

You could improve the previous solution by breaking the loop if you find any asymmetry:

javascript
const isPalindrome = n => {

    let x = n, y = 0, length_n, length_y

    // E.g. n = 125
    // 1. x = 12 y = 5
    // 2. x = 1  y = 52
    // 3. x = 0  y = 521
    while(x > 0){

        y = (y * 10) + 10 * (x/10 % 1).toFixed(2)
        x = Math.floor(x/10)

        // You can break the loop if n doesn't start with y
        // No need to wait until the end of the loop
        length_n = parseInt(Math.log10(n)) + 1
        length_y = parseInt(Math.log10(y)) + 1

        if(y !== Math.floor(n/(10 ** (length_n - length_y))))
            break

    }

    return n === y

}