LeetCode: Count Nice Pairs In An Array Solution

1/**
2 * @param {number[]} nums
3 * @return {number}
4 */
5var countNicePairs = function (nums) {
6  const getRev = num => Number(String(num).split("").reverse().join(""))
7  return (
8    Array.from(
9      nums
10        .map(num => num - getRev(num))
11        .reduce((acc, el) => acc.set(el, (acc.get(el) || 0) + 1), new Map())
12        .values()
13    )
14      .filter(x => x > 1)
15      .map(x => (x * (x - 1)) / 2)
16      .reduce((acc, el) => acc + el, 0) %
17    (1e9 + 7)
18  )
19}