groupBy<K> method

Map<K, List<T>> groupBy<K>(
  1. K keySelector(
    1. T
    )
)

Groups elements of the original collection by the key returned by the given keySelector function applied to each element and returns a map where each group key is associated with a list of corresponding elements.

The returned map preserves the entry iteration order of the keys produced from the original collection.

Implementation

Map<K, List<T>> groupBy<K>(K Function(T) keySelector) {
  return groupByTo({}, keySelector);
}