public static IRxVal <Option <B> > optFlatMap <A, B>(
this IRxVal <Option <A> > source, Fn <A, IRxVal <Option <B> > > extractor
) =>
source.flatMap(aOpt =>
aOpt.fold(
() => RxVal.cached(F.none <B>()),
extractor
)
);
public static IRxVal <Option <B> > optFlatMap <A, B>(
this IRxVal <Option <A> > source, Fn <A, Option <IRxVal <Option <B> > > > extractor
) =>
source.flatMap(aOpt =>
aOpt.flatMap(extractor).getOrElse(RxVal.cached(F.none <B>()))
);