Firestore: get document back after adding it / updating it without additional network calls

As you have probably seen in the documentation of the Node.js (and Javascript) SDKs, this is not possible, neither with the methods of a DocumentReference nor with the one of a CollectionReference.

More precisely, the set() and update() methods of a DocumentReference both return a Promise containing void, while the CollectionReference's add() method returns a Promise containing a DocumentReference.

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Side Note (in line with answer from darrinm below): It is interesting to note that with the Firestore REST API, when you create a document, you get back (i.e. through the API endpoint response) a Document object.

This appears to be an arbitrary limitation of the the Firestore Javascript API. The Firestore REST API returns the updated document on the same call.

https://firebase.google.com/docs/firestore/reference/rest/v1beta1/projects.databases.documents/patch