问题
According to this What is firestore Reference data type good for?. Currently it looks like you have to do a round trip to fetch the data for each document reference in your original query.
Is this on the roadmap to do this expand/aggregation in the cloud?
回答1:
You are correct, a GraphQL style server-side expansion of references is not possible in Cloud Firestore.
Completely understand the desire, however this is not currently on our roadmap to support.
来源：https://stackoverflow.com/questions/47100446/firestore-document-references-can-you-expand-the-document-server-side