Question: Accessing Loadable state outside CountriesList about clean-architecture-swiftui HOT 4 OPEN

Hey @Cobrijani

Thank you for the feedback! Regarding your question, the state management in SwiftUI always complies with the "single source of truth" principle, so you'll need to choose the "owner" for this Loadable.

You have three options: parent component, child component, and AppState.

The AppState would make it accessible to the rest of the app - useful for some cases, but certainly not for all.

With regards to the parent - child parity, I'd bet that most of the time the parent should be the owner, and the child should consume the value through Binding. This way both parent and child will see the changes in the Loadable while either one can kick off the loading process by supplying the Binding to the Interactor (Service).

from clean-architecture-swiftui.

Hi @nalexn
Thanks for your answer! It completely makes sense to choose parent as owner in this case!

How would you implement parent ownership in case of view model approach?
Is LoadableSubject instead of Loadable needed in the view model in order to get the binding?

I tried creating Loadable Publisher in the parent and passing it to the child, but the updates in the parent are not being triggered when the data load is being triggered in the child view.

Pseudo Code Snippet:

struct CountriesList: View {

  @ObservedObject private(set) var viewModel: ViewModel
   var body: some View {
        // in this case child will trigger the loading of the countries in this loadable
        // parent will pass .notRequested
        Child(countries: self.viewModel.countries)
   }
}

extension CountriesList {
    class ViewModel: ObservableObject {
        
        // ... 
        @Published var countries: Loadable<LazyList<Country>>
 
       init(...){
          // inits ...

         // can something like this work? Do i need loadable subject store above and not just publisher?
         $countries.sink {
                // register when child loads the component to show something in the parent
            }.store(cancelBag)
       }
}

Thanks!

from clean-architecture-swiftui.

Ok, the Child should consume the Binding in the init:

struct Child {
    @Binding var value: Int

    init(value: Binding<Int>) {
        self._value = value
    }
}

And you should pass the binding from the parent this way:

Child(countries: self.$viewModel.countries)

Note that self.viewModel.$countries will give you a Publisher, not a Binding.

I recommend reading my other post where I cover these topics.

from clean-architecture-swiftui.

Hi @nalexn,

Great, thanks!

Best regards

from clean-architecture-swiftui.