update method
Updates fields in the document referred to by this DocumentReference
.
The update will fail if applied to a document that does not exist.
Nested fields can be updated by providing dot-separated field path strings.
@param data An object containing the fields and values with which to update the document. @param precondition A Precondition to enforce on this update. @throws Error If the provided input is not valid Firestore data. @return A Promise resolved with the write time of this update.
Implementation
external JSPromise<WriteResult> update(
JSObject data, [
Precondition precondition,
]);