Map a Future for both Success and Failure

Question

I have a Future[T] and I want to map the result, on both success and failure.

Eg, something like

val future = ... // Future[T]
val mapped = future.mapAll         


        

Answer 1

In a first step, you could do something like:

import scala.util.{Try,Success,Failure}

val g = future.map( Success(_):Try[T] ).recover{
  case t => Failure(t)
}.map {
  case Success(s) => ...
  case Failure(t) => ...
}

where T is the type of the future result. Then you can use an implicit conversion to add this structure the Future trait as a new method:

implicit class MyRichFuture[T]( fut: Future[T] ) {
  def mapAll[U]( f: PartialFunction[Try[T],U] )( implicit ec: ExecutionContext ): Future[U] = 
    fut.map( Success(_):Try[T] ).recover{
      case t => Failure(t)
    }.map( f )
 }

which implements the syntax your are looking for:

val future = Future{ 2 / 0 }
future.mapAll {
  case Success(i) => i + 0.5
  case Failure(_) => 0.0
}