leetcode-7 整数反转

/**
 * @param {number} x
 * @return {number}
 */
var reverse = function (x) {
  let newX = 0;
  const isNegative = x < 0;
  while (x) {
    const num = x % 10;
    newX *= 10;
    newX += num;
    x = isNegative ? Math.ceil(x / 10) : Math.floor(x / 10);
  }
  if (newX > Math.pow(2, 31) - 1 || newX < -Math.pow(2, 31)) {
    return 0;
  }
  return newX;
};
// console.log(reverse(-123));