unfortunately this is not flexible enough to handle field value as field value output is different from input

especially server timestamp, also apply to number and array where they can accept field value

we still need better wrapper

const converter = {

toFirestore: (data: { createdAt: Firestore.FieldValue }) => data, // server time stamp

fromFirestore: (snap: FirebaseFirestore.QueryDocumentSnapshot) =>

snap.data() as {

createdAt: Firestore.Timestamp // timestamp object

},

}

firestore().collection('users').withConverter(converter) // type error