groupBy static method
Group by objects according to key/value pair
Example:
groupBy(list, fn)
Implementation
static Map<dynamic, List<dynamic>> groupBy(
Iterable<dynamic> itr, dynamic Function(dynamic) fn) {
// ignore: always_specify_types
return Map.fromIterable(itr.map(fn).toSet(),
// ignore: always_specify_types
value: (i) => itr.where((v) => fn(v) == i).toList());
}