code: function groupByTwoArguments(keySelector, inner) {
              let keyComparator, elementSelector;
              if (isKeyComparator(inner)) {
                  keyComparator = inner;
                  elementSelector = (elem) => elem;
              }
              else {
                  keyComparator = __defaultEqualityCompareFn;
                  elementSelector = inner;
              }
              return groupByThreeArguments(keySelector, elementSelector, keyComparator);
          }
docs: /*
  GroupBy(keySelector, keyComparator)
  GroupBy(keySelector, elementSelector)
  GroupBy(keySelector, resultSelector)