groupBy method

Map<String, List<V>> groupBy(
  1. String funcGroupKeyResolver(
    1. V item
    )
)

Implementation

Map<String, List<V>> groupBy(String Function(V item) funcGroupKeyResolver) {
	Map<String, List<V>> odRet = Map<String, List<V>>();
	for (V item in this.values) {
		String key = funcGroupKeyResolver(item);
		odRet.putIfAbsent(key, () => [ ]);
		odRet[key]!.add(item);
	}
	return odRet;
}