[Leetcode] 7. Reverse Integer Typescript

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: number): number {
  let isNegative = false;
  let inputNumber = x;
  if (x < 0) {
    isNegative = true;
    inputNumber = -x;
  }

  const reversedNumber = Number(inputNumber.toString().split('').reverse().join(''));

  if (reversedNumber > Math.pow(2, 31) || x < Math.pow(-2, 31) - 1) {
    return 0;
  }

  return isNegative ? -reversedNumber : reversedNumber;
}