How to limit query to just few fields?

[vladaman]

We have a collection, let's say "Users" and we'd like any user to be able to query list of all user names but not other fields. In firestore we can set restriction rule to specific fields but running query just queries all fields.

We get an error:

Unhandled Exception: [cloud_firestore/permission-denied] The caller does not have permission to execute the specified operation.