Wait and accumulate values until other observable fires

Question

I have two observables and I want just one value from each. In case the observable2 pushes a value first I would like to wait and keep the received value until observable1 pushes a value and push kept value then. Basicaly the same behaviour as with skipUntil with the difference that I don't want to discard the value. I guess it I could do it by concatting the observables but I would like to keep them separate.

observable1
  .take(1)
  .subscribe(doSomething)

observable2
  .take(1)
  // .skipUntil(observable1)
  .waitUntil(observable1) // Something like this
  .subscribe(doSomethingElse)

Answer 1

This will wait for observable1 to push and then switches to observable2:

observable1.switchMap(() => observable2)
           .take(1)
           .subscribe(doSomethingElse);

If you want observable1 to only fire once (for example if you subscribe to it somewhere else like in your example), consider using .share().