Sharing piece of state into a optional child of a child state

[mapedd]

Hello. I'm trying to figure what's the best way to model something like this

I have a MainState that holds into an records array of Records.
MainView is showing and manipulating it.
MainState has a child called SummaryState that does not need to know anything about the records. But then SummaryState has an optional piece of state called StatisticsState, that wants to show records in various way by filtering/sorting it.

I think using Environment to read/write to records array would remove a lot of the benefits of using TCA.
Adding records to SummaryState just so that it's then passed to StatisticsState seems like a heavy solution that will be difficult to maintain.

Any suggestions?

[Alex293]

You can move the navigation to the stats feature up in the main feature (stat feature become a child of main feature) or your summary feature could take a viewBuilder closure so it can build and navigate to stats without knowing how to build it. Then when you build the summary view you pass a view builder.

One thing that I like to keep in mind is that your features (state, action, reducers ...) structure can vastly differ from the navigation hierarchy. Also as there is only one store you can pass a non scoped store to subviews, just be careful to scope it where you use it in viewStores.

[mapedd]

Those are some good suggestions @Alex293 , thanks 👍

[mapedd]

For the first suggestion, I think the problem would be, that action that is sent from the SummaryView ( so should be of type SummaryAction) needs to then referenced in the MainView in the sheet presentation. I'd expect to use only action from the single domain in the view for a given state.

MainView.swift


  .sheet(
        isPresented: viewStore.binding(
          get: \.showStatistics,
          send: { $0 ? SummaryAction.showStatistics : SummaryAction.hideStatistics }
        )
      )

[Alex293]

If main is the entry point it can get access to all the actions which you can wrap like :

.sheet(
        isPresented: viewStore.binding(
          get: \.showStatistics,
          send: { .summary($0 ? SummaryAction.showStatistics) : SummaryAction.hideStatistics) }
        )
      )

but really if main dispatches and interprets the actions for navigating those action should go into main feature.

I would do something like:

enum SummaryAction {
  ...
  case delegate(DelegateAction)

  enum DelegateAction {
    case findAGoodnameToPushStatistics
  }
}

and you return .none in Summary reducer but in your main reducer you handle this action.

The idea behind having a separate delegate is to make clear that you don't have to do anything in the reducer but that those need to be handled by the user of the feature.