scala two options defined, return first, else return second

Question

If I have optionA, and optionB, how can I return optionA if both are defined and optionB is both are not defined.

Basically, I am trying to rewrite this

val result: Option[Long] = 
  if(optionA.isDefined && optionB.isDefined)
     optionA
  else
     optionB

No, optionA.orElse(optionB) is not the same and broke our test cases. BOTH options must be defined and we want to use optionA. IF optionA is defined and optionB is not defined, we want None.

Someone marked my question as a duplicate which it is not. I was having trouble but finally stumbled upon the answer....

ok, I think I got it and I definitely think it is less human readable

optionA.flatMap { aId =>
    optionB.map(bId => bId).orElse(Some(aId))
}

for added clarity. our truth table is thus

optionA.isDefined  optionB.isDefined   resultNeeded
    None               None               None
    Some(a)            None               None
    None               Some(b)            Some(b)
    Some(a)            Some(b)            Some(a)

thanks

Answer 1

You can use pattern matching :

(optionA, optionB) match {
  case (Some(_), Some(_)) => optionA
  case _ => optionB
}