Firestore Mirror Database

FirestoreMirror.swift

// These methods removes the necessity of having to clear the array for each run as it just mirrors whatever the document data is.
self.array = snapshot!.documents.flatMap({Model(dictionary: $0.data())})
DispatchQueue.main.async {
  self.tableView.reloadData()
}

// Or this is even better...
// Only check for document changes
snap.documentChanges.forEach {
    diff in

    // Check only for newly added documents
    if diff.type == .added {
        do {
            let object = try Model(dictionary: diff.document.data(),
                                  documentId: diff.document.documentID)
            // Append
            self.array.append(object)
            DispatchQueue.main.async {
                self.tableView.reloadData()
            }
        }
        catch let error {
            /* Handle object casting error */
        }
    }
}