An options object that configures the behavior of set() calls in
DocumentReference, WriteBatch and Transaction. These calls can be
configured to perform granular merges instead of overwriting the target
documents in their entirety.
Param: merge
Changes the behavior of a set() call to only replace the
values specified in its data argument. Fields omitted from the set() call
remain untouched. If your input sets any field to an empty map, all nested
fields are overwritten.
Param: mergeFields
Changes the behavior of set() calls to only replace
the specified field paths. Any field path that is not specified is ignored
and remains untouched. If your input sets any field to an empty map, all
nested fields are overwritten.
An options object that configures the behavior of
set()calls inDocumentReference,WriteBatchandTransaction. These calls can be configured to perform granular merges instead of overwriting the target documents in their entirety.