mapOrElseForUndefinable

Return the result of transformer with using input as an argument for it if input is not undefined. Otherwise, return the result of recoverer.

Basically, this operation is a combination map() and unwrapOrElse().

• U must not be Undefinable<*>.
  • If the result of transformer is undefined, this throw an Error.
  • If the result of recoverer is undefined, this throw an Error`.
• If you'd like to accept Undefinable<*> as U, use a combination andThen() and orElse().