groupAnagrams = (words, map = new Map()) => {
    if (!words.length) return [];

    groupWords(words, map);    /* Time O(N * (K * log(K)) | Space O(N * K) */

    return [ ...map.values() ];/* Time O(N)               | Space O(N * K) */
}
Sort - HeapSort Space O(1) | QuickSort Space O(log(K))
Hash Map - Adjacency List
Time O(N * (K * log(K))) | Space O(N * K)
https://leetcode.com/problems/group-anagrams/
@param {string[]} strs
@return {string[][]}