Improving MVP in Scala

Question

The classical strongly typed MVP pattern looks like this in Scala:

trait IView { }

trait Presenter[View <: IView] {  // or have it as an abstract type member
  val view : View
}

case class View1(...) extends IView { ... }

case object Presenter1 extends Presenter[View1] { 
  val view = View1(...)
}

Now, I wonder if there is any nice way to improve on it which I am missing...

Answer 1

Nice thing about MVP pattern is that it makes your UI code unit testable.

I'd suggest you to avoid instantiating view in presenter and pass it to constructor. That will allow you to just mock out the View and unit test the Presenter.

Replace you code

case object Presenter1 extends Presenter[View1] { 
  val view = View1(...)
}

with

case object Presenter1(val view: View1) extends Presenter[View1] { 
  ...
}