How to do a firestore query in chronological order on creation

Question

I built a collection and added some documents sequentially (a few seconds apart). firestore generated each doc.id automatically.

In the documentation it says each doc.id key consists of a timestamp part and random part (presumably to ensure there are no key collisions). Edit: I had read this on an unrelated blog post, so I've removed this to avoid confusion.

Since If the key were to contain some (hidden) chronology, is it possible to do a firestore query based on this key and thus get the result set in ascending or descending chronological order?

Answer 1

Unfortunately, Cloud Firestore auto-generated IDs do not provide any automatic ordering, and cannot be relied-upon to be chronological. To order your documents chronologically, you should add your own timestamp field to the documents.

From the Firestore add a document documentation:

Important: Unlike "push IDs" in the Firebase Realtime Database, Cloud Firestore auto-generated IDs do not provide any automatic ordering. If you want to be able to order your documents by creation date, you should store a timestamp as a field in the documents.