I’m not sure what you mean, but the only difference I see between your code and mine is that you update the status inside the map, I do it in finalize.

RxJS now is in V6 and there is no more .chainable oprators, instead it uses pipable operators, so I think that might answer your question, in other words, before Rxjs6 I was right, after RxJS you are right

check this out too: http://reactive.how/rxjs/explorer