Intervals Between Identical Elements LeetCode solution in JavaScript

1
var getDistances = function (arr) {
2
  const map = new Map();
3
  const result = new Array(arr.length).fill(0);
4

5
  for (let i = 0; i < arr.length; i++) {
6
    const num = arr[i];
7
    const val = map.get(num) || {
8
      count: 0,
9
      sum: 0,
10
    };
11
    result[i] += val.count * i - val.sum;
12
    val.sum += i;
13
    val.count++;
14
    map.set(num, val);
15
  }
16
  map.clear();
17

18
  for (let i = arr.length - 1; i >= 0; i--) {
19
    const num = arr[i];
20
    const val = map.get(num) || {
21
      count: 0,
22
      sum: 0,
23
    };
24
    result[i] += val.sum - val.count * i;
25
    val.sum += i;
26
    val.count++;
27
    map.set(num, val);
28
  }
29

30
  return result;
31
};