state_example: flutter command viewmodel

notes.viewmodel.dart

class NotesViewModel {
  NotesState state = NotesState.initial();

  Command<String, String> inputChangedCommand;
  Command<String, NotesState> updateNotesCommand;

  NotesViewModel() {
    inputChangedCommand = Command.createSync((x) => x, '');
    updateNotesCommand = Command.createSync((input) {
      state = state.copyWith(notes: state.notes.concat(input));
      inputChangedCommand.execute('');

      return state;
    }, NotesState.initial());
  }
}