reverse_integer.js

// 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 [-231, 231 - 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

// Constraints: -231 <= x <= 231 - 1

// ----------------------------------------------------------------------------------------------------------------

function reverse(x) {
    let reverseInt = 0;
    let isNegative = x < 0;

    x = Math.abs(x);

    while (x > 0) {
        let lastDigit = x % 10;
        reverseInt = reverseInt * 10 + lastDigit;
        x = Math.floor(x / 10);
    }

    return isNegative ? -reverseInt : reverseInt;
}

let nums = -44587;
let reverseInt = reverse(nums);

console.log(reverseInt);