Next Greater Element III LeetCode solution in JavaScript

1
var nextGreaterElement = function (n) {
2
  const MAX_VALUE = 2 ** 31 - 1;
3
  const nums = `${n}`.split("");
4
  let findPos;
5

6
  for (let index = nums.length - 2; index >= 0; index--) {
7
    if (nums[index] < nums[index + 1]) {
8
      findPos = index;
9
      break;
10
    }
11
  }
12

13
  if (findPos === undefined) return -1;
14
  for (let index = nums.length - 1; index >= 0; index--) {
15
    if (nums[index] > nums[findPos]) {
16
      [nums[index], nums[findPos]] = [nums[findPos], nums[index]];
17
      break;
18
    }
19
  }
20

21
  const mantissa = nums
22
    .slice(findPos + 1)
23
    .sort((a, b) => a - b)
24
    .join("");
25
  const result = Number(nums.slice(0, findPos + 1).join("") + mantissa);
26
  return result > MAX_VALUE ? -1 : result;
27
};