Suggestion: overload `useSubscription` to add support for observer objects

[OliverJAsh]

The subscribe function of an Observable can receive an observer object:

const observer = { next: myNext, error: myError, complete: myComplete }

ob$.subscribe(observer)

It would be great if useSubscription allowed the same, so we can do this:

useSubscription(ob$, observer)

… instead of this:

useSubscription(ob$, observer.next, observer.error, observer.complete)

[crimx]

Hi, we purposely did not support the observer object for performance reason. It would create less garbage and easier to handle with the current pattern.

Do you have a real world use case that would benefit from this pattern?

[OliverJAsh]

we purposely did not support the observer object for performance reason. It would create less garbage and easier to handle with the current pattern.

This seems like micro performance to me. I feel like it would be better to be consistent the way subscribe works in RxJS, and then let users decide which overload they would like to use.

Side note: the next version of RxJS will deprecate the subscribe overload which accepts multiple functions. https://docs.google.com/presentation/d/1pqbojTcQGUiQ6b-aA7bGl2rmboChsZQnR-LZ1cDpkT4/edit#slide=id.g82d9b6b050_0_129.

Do you have a real world use case that would benefit from this pattern?

Yes, we have a hook that creates an observer:

export type DataFetchingActionsObserver = Rx.PartialObserver<Array<OldOrNewAction>>;

export const createDataFetchingActionsObserver = ({
  dispatch,
  history,
}: {
  dispatch: Dispatch;
  history: RouterHistory;
}): DataFetchingActionsObserver => ({
  next: batchDispatch(dispatch),
  error: handleDataFetchingError(dispatch, history),
});

export const useDataFetchingActionsObserver = () => {
  const dispatch = useDispatch();
  const history = useHistory();
  return createDataFetchingActionsObserver({ dispatch, history });
};

I would like to use this observer with the useSubscription hook.

[crimx]

You are right. We should add this and let user decide.

[OliverJAsh]

I'll raise a PR.

Thanks for the fantastic lib btw. Migrating the Unsplash app over from rxjs-hooks, this is much more flexible.

[crimx]

Thanks for trying observable-hooks and the PR! Let me know if there is any blocker.

[crimx]

Hi @OliverJAsh are you still working on this one?

[OliverJAsh]

Hey I haven't had the chance sorry, I still really want it though!