`no-ignored-subscribe` may also support `Subscribable`

[dubzzz]

Hi,

First of all thanks a lot for this project. I'm not sure the issue is really an issue. Before trying to suggest a fix I wanted to make sure that the idea was relevant.

Today, the rule no-ignored-subscribe only checks the ignored subscribe for Observable. See https://github.com/cartant/eslint-plugin-rxjs/blob/main/source/rules/no-ignored-subscribe.ts#L28

But it seems that ideally it should check ignored subscribe for any Subscribable (an Observable is a Subscribable). What's your opinion?

[cartant]

Do you have a use case for this? I.e. an example of someplace that user-land code would be subscribing to a Subscribable? If not, I'm inclined to leave it as it is, for the moment. At least until this issue is discussed/resolved.

[dubzzz]

Not anything in a public repository unfortunately.

Why Subscribable and not Observable?

I have a function that receives instances of Observable but from an user point of view I only wanted to request a minimal subset of the API: the Subscribable part (basically mostly for typings).

Let's take an example with something close:

function useWatch<T>($s: Observable<T>): T | undefined {
  const [value, setValue] = useState<T>();
  useEffect(() => {
    const s = $s.subscribe(setValue);
    return () => s.unsubsribe();
  }, [$s]);
  return value;
}

From a caller point of view this constraint on Observable could be relaxed. Any Subscribable would work with this code. Additionally the smaller the size of the input type the simpler it is to mock in the tests.

Currently I am still using Observable to have eslint complaining for missing unsubscribe. But actually I'd like to make this piece of code able to deal with simple Subscribable (if I am not wrong it's just an interface).

[cartant]

https://github.com/cartant/eslint-plugin-rxjs/blob/main/CHANGELOG.md#320-2021-04-25

[dubzzz]

Thanks a lot 😁