Reverse Integer

Given a signed 32-bit integer x, return x with its digits reversed. If reversing x causes the value to go outside the signed 32-bit integer range [-2^31, 2^31 - 1], then return 0.

Assume the environment does not allow you to store 64-bit integers (signed or unsigned).

Example 1:

Input: x = 123

Output: 321

Example 2:

Input: x = -123

Output: -321

Example 3:

Input: x = 120

Output: 21

Example 4:

Input: x = 0

Output: 0

Solution in JavaScript

var reverse = function(x) {
    let z = ''
    let isReady = true
    let answer
    if (x < 0) {
        x = -x
        isReady = false
    }
    x += ''
    for (let i = x.length - 1; i >= 0; i--) {
        z += x[i];
    }
    
    if (isReady) {
        answer = Number(z)
    } else {
        answer = -Number(z)
    }
    
    
    return answer >= -Math.pow(2, 31) && answer <= Math.pow(2, 31) - 1 ? answer : 0
};