Firebase - Firestore - get key with collection.add()

Question

I am facing a problem with the new Firestore from Firebase.

Situation: I have a collection('room')

I create room with collection('room').add(room)

---

What I'm trying to do: I need to update a room.

For this, I use: collection('room').doc(ROOM_ID).update(update)

So I need to add ROOM_ID in the document in my collection:

|room
    ROOM_ID
        id:ROOM_ID,
        someContent: ForTheQuery

---

Is there a possible way to achieve that?

An alternative is to create myself a generated ID with:

collection('room')
.doc(someId)
.set({
    id: someId,
    someContent: ForTheQuery
});

but i want to avoid it.

Answer 1

Waitting for answers