Firebase Flutter Script

firebase.dart

getDataListen() {
  CollectionReference reference = Firestore.instance.collection('jobs');
  reference.snapshots().listen((querySnapshot) {
    List<Joblist> todoList = List<Joblist>();
     for (int i = 0; i < querySnapshot.documents.length; i++) {
        todoList.add(Joblist.fromMap(querySnapshot.documents[i]));
      }
      setState(() {
        joblist = todoList;
      });
});

listenFirebase() {
  Firestore.instance
      .collection('message')
      .where("user", isEqualTo: "Deny")
      .snapshots()
      .listen(
          (data) => data.documents.forEach((doc) => print(doc["message"])));
}

createData() {
  Firestore.instance
      .collection('books')
      .document()
      .setData({'title': 'title', 'author': 'author'});
}

removeData() {
  Firestore.instance
      .collection('books')
      .document('-LNWoNygtcsNXrLz0Y_c')
      .delete();

  print("Data deleted!");
}

getData(key){
   DocumentSnapshot doc =
          await Firestore.instance.collection('order').document(key).get();
      item.email = doc["email"];
      item.firstName = doc["first_name"];
      item.lastName = doc["last_name"];
      item.username = doc["username"];
      item.billing = doc["billing"];
}