Add effectful groupByNelA(A => F[B]): F[SortedMap[B, NonEmptyList[A]]]

[ronanM]

Add to cats.syntax.ListOps[A]:

def groupByNelA[F[_] : Applicative, B](f: A => F[B])(implicit B: Order[B]): F[SortedMap[B, NonEmptyList[A]]]

An optimised version of:

as.traverse(a => f(a).tupleLeft(a)).map(_.groupByNel(_._2).mapValues(_.map(_._1)))

[pk044]

@ronanM are you perhaps planning to implement this one? I can do it in case it's free to take :)

[ronanM]

It's free. ;-)

[pk044]

i'll try to implement that then :)