Firestore force create ancestor documents - firebase

Question

I'm creating a firestore document that's not at the root level of an existing collection but somewhat deeper:
const response = await addDoc(
collection(
firestore,
'stats', //collection
'dayStats', //document
'years', //collection
'2023', //document
'january', //collection
),
statData
);
At the time of creation, the entire collection structure does not yet exist, but only a part of it (stats/dayStats/years).
What ends up happening is that stat document is successfully created in the correct place, but not the intermediary documents. They are in italics and there's a warning for them saying "This document does not exist, it will not appear in queries or snapshots".
I suppose this means that I need to be explicit about force creating these intermediary documents? Is there some kind of a config I can pass to the function, that would just create the intermediary documents in the path, if they to not yet exist? Or do I need to do this by hand each time I'm creating a document, that has a ancestor document that might not exist?

Answer 1

The intermediary documents are in italics and there's a warning for them saying "This document does not exist, it will not appear in queries or snapshots". I suppose this means that I need to be explicit about force creating
these intermediary documents?
Indeed the intermediary parent documents don't exist and you need to create them.
Is there some kind of a config I can pass to the function, that would
just create the intermediary documents in the path, if they to not yet
exist?
No
Do I need to do this by hand each time I'm creating a document, that
has a ancestor document that might not exist?
Yes you need, in your code, to create the parent documents. The best is to use a Batched Write which ensures that both the parent and children docs are created via an atomic operation.
For example:
import { writeBatch, doc } from "firebase/firestore";
const batch = writeBatch(firestore);
const ref1 = doc(firestore, "stats", "dayStats");
batch.set(ref1, {...});
const ref2 = doc(ref1, "years", "2023");
batch.set(ref2, {...});
const ref3 = doc(ref2, "january"); // DocID will be auto-generated
batch.set(ref3, statData);
await batch.commit();