将[L，R]转换为L和R的公共超类型的值

Question

If I have a value of type Either[A, B] , where A extends T and B extends T , how can I most easily get a value of type T ? Anything more elegant than pattern matching?

Answer 1

Use merge :

val e: Either[A, B] = ???
val result: T = e.merge

Answer 2

You can use fold with the identity function on both sides - will the one that exists:

val e: Either[A, B] = ???
val result: T = e.fold(identity[T], identity[T])