How do I get list of the document ID's inside a collection without getting the content of the documents in Firestore?

Question

I want to do something like:

final collectionReference = Firestore.instance.collection('myCollection');
final List<String> documentList = collectionReference.getDocList();

OR

final query = collectionReference.orderBy('lastUpdated', descending: true).limit(100);
final List<String> documentList = query.getDocList();

Currently when we use get() or query.getDocuments() it will return the whole Document list and all contents along with it. But you know that we wanna optimize reads thus we make use of the 1MiB limit of each Documents. Thus we don't wanna download the whole document's contents. Rather we just need the IDs for other usage. Is there a way to do this?

Thanks

Answer 1

There no way to do this with the Flutter APIs (or any of the web or mobile clients).

The only way is with backend code, where you have a method like select() (link to the nodejs API) on Query that lets you select which document fields to return. So, you could have your app call a backend to return the document IDs, but not directly in the app.

If you must query from the client, consider moving fields unnecessary for queries to documents in anther collection with the same IDs, and request them only when needed.