1
var smallestNumber = function (num) {
2
  let arr = Array.from(String(num));
3
  if (num > 0) {
4
    arr.sort((a, b) => {
5
      return a - b;
6
    });
7
  } else {
8
    arr.sort((a, b) => {
9
      return b - a;
10
    });
11
  }
12
  for (let i = 0; i < arr.length; i++) {
13
    if (arr[i] != 0) {
14
      [arr[0], arr[i]] = [arr[i], arr[0]];
15
      break;
16
    }
17
  }
18
  return arr.join("");
19
};