[WorldMaker]

I've had some success with writing Async Generator functions in mixed RxJS/IxJS pipelines.

  async *function someMapOperation() {
    const { value, meta } = await getValue(…)
    doSomething(meta)
    yield value
    for await (const { value, meta } of AsyncIterableX.from(mergeAll(…).pipe(takeUntil(…)))) {
      doSomething(meta)
      yield value
    }
    // …
  }

(I've done similar things in C#, as well, with its Rx/Ix pair.)

You are right, there are still good cases where being able to write the "state machine" of a complex flow as an async (generator) function makes it a lot easier to reason with. The nice thing is that Observables work well with AsyncIterables and a pipeline doesn't have to be just one or the other.