I am using firebase and I'm a bit confused concerning security rules.

Consider the following data structure :

{
  viewable:boolean,
  prop1: ...;
  map : { viewable: boolean ... }
}

As you see my structure can contains properties with a nested viewable property. I want to be able to make queries where objects with the property viewable == true returns the object with the viewable properties, but nested objects with a viewable == false are omitted from the returned results.

At the moment, I tried some security rules but objects with "viewable == false" are still in the result.

And then I saw in the documentation that firebase rules can't be used to filter nested field...

I can't use Cloud Functions either because then I won't be able to observe firestore database changes (with the snapshotChanges API).

Do you know if it is possible to achieve?

Regards