update method
Updates fields in the document referred to by the provided
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 documentRef A reference to the document to be updated.
@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 This Transaction
instance. Used for chaining method calls.
Implementation
external Transaction update(
DocumentReference documentRef,
JSObject data, [
Precondition precondition,
]);