An options object that configures the behavior of
get() calls on
Query. By providing a
GetOptions object, these
methods can be configured to fetch results only from the server, only from
the local cache or attempt to fetch results from the server and fall back to
the cache (which is the default).
Describes whether we should get from server or cache.
default (or not setting at all), causes Firestore to try to
retrieve an up-to-date (server-retrieved) snapshot, but fall back to
returning cached data if the server can't be reached.
server causes Firestore to avoid the cache, generating an
error if the server cannot be reached. Note that the cache will still be
updated if the server request succeeds. Also note that latency-compensation
still takes effect, so any pending write operations will be visible in the
returned data (merged into the server-provided data).
cache causes Firestore to immediately return a value from the
cache, ignoring the server completely (implying that the returned value
may be stale with respect to the value on the server.) If there is no data
in the cache to satisfy the
return an error and
QuerySnapshot.get() will return an empty
QuerySnapshot with no documents.