In Flutter, should a provider wrap the datamodel, or should it implement each member of the model as a variable?

Question

I wrote an app last year where I needed to update a model across multiple screens, so I used provider with changeNotifier. I implemented the provider like so;

class SurveyProvider with ChangeNotifier, DiagnosticableTreeMixin{
  String name = "";
  String postCode= "";
  
  void addSurvey(Survey survey){
    this.name = survey.name;
    this.postCode = survey.postCode;
    notifyListeners();
}

The provider is for the data model below. To keep things simple, I've reduced it to just two variables.

class Survey{
  final String name;
  final String postCode;
}

I implemented each variable of the model as a variable inside the provider. Should I have implemented the entire model inside the provider like this?

class SurveyProvider with ChangeNotifier, DiagnosticableTreeMixin{
  Survey survey;
  
  void addSurvey(Survey survey){
    this.survey = survey;
    notifyListeners();
}

I'm not sure which way is the correct way to do this, but I have a feeling the way I've done it is wrong.

Answer 1

There is not a universally correct approach to state management, but I would say that what you did was not wrong.

The first approach is better when you have a 1 to 1 link between the object and the provider.

However, the second option is more solid if you need a provider for complex and different entities, since it allows you to separate the objects logic from their provider's.

The best solution depends on the size and complexity of your project.