groupBy package:relude

groupBy :: (Foldable f, DynamicMap t, Val t ~ NonEmpty a, Monoid t) => (a -> Key t) -> f a -> t
relude Relude.Extra.Group
Groups elements using results of the given function as keys. 
>>> groupBy even [1..6] :: HashMap Bool (NonEmpty Int)
fromList [(False,5 :| [3,1]),(True,6 :| [4,2])]