Set[(A, B)] toSetMap

Helper.scala

/*
I needed a quick transformation like `toMap` on Set[(A, B)] that retains all of B's values.

Thanks to https://twitter.com/br_waldteufel/status/765831435244670976 this is now much cleaner than the first revision :)

example:

scala> Set(("A", 1), ("A", 2), ("B", 1)).toSetMap
res0: Map[String,Set[Int]] = Map(A -> Set(1, 2), B -> Set(1))

*/

object Helper {
  def setToMapOfSets[A, B](x: Set[(A, B)]): Map[A, Set[B]] = {
    x.groupBy(_._1).mapValues(_.map(_._2))
  }

  implicit class richSeqSet[A, B](self: Set[(A, B)]) {
    def toSetMap: Map[A, Set[B]] = setToMapOfSets(self)
  }
}