mobx computed value not updating(Observe) on UI at the first time but after reload

Question

I'm using MobX to manage my global state of the app. The problem is I'm using some computed values om my UI but those values not updating on UI but when i print those values in my mobx modal those computed values are computed correctly.

This is my model.

abstract class _User with Store {
  _User(this.name, this.subjects);

  @observable
  String name;

  @observable
  List<Spend> subjects;

  @computed
  int get totalSubjects => this.subjects.length;

  @action
  void addSubject(String name) {
    subjects.add(Spend(name));
    print(totalSubjects);
    // If i print the value this gives me correct length of subjects array, But this not oberving on UI
  }
}

Only the computed value is not updating. But when i add the subject that subject reflect correctly.

I'm using flutter_mobx: ^1.1.0+2 and sdk: ">=2.7.0 <3.0.0"

Solution

adding removing or any types of updates to a List is not observed only asigning does, if you want use a List which an be observed Use ObservableList