What is switchMap equivalent to in unflattened form?

问题

If flatMap() is equivalent to map().mergeAll(), then what is switchMap() equivalent to ?

回答1:

The switchMap() operator is equivalent to using map().switch().

Since the switch() operator works only with higher-order Observables the preceding map() has to return an Observable. There's no switchAll() operator because the switch() operator already works with higher-order Observables(just like all *all() operators).

来源：https://stackoverflow.com/questions/43165848/what-is-switchmap-equivalent-to-in-unflattened-form