TabView + Destinations for navigation

[AndrewMalyhin]

Hey!

Trying to learn from isowords codebase.

There is a nested struct called Destinations
public struct Destinations: ReducerProtocol, and I see how it works with child states via public var destination: Destinations.State? stored in a Parent state. Then you may send an action using tag case setNavigation(tag: Destinations.State.Tag?) from the View, and it all works.

My question: is it possible to use this Destinations approach with TabView?

I doubt it since I have to provide all child Stores to child views in this method.
TabView(selection: <#T##Binding<Hashable>?#>, content: <#T##() -> View#>)

So it means that navigation will be split between Destinations and then some var in the parent state with tabbar Tag.
Should I treat Destinations as something that sends the user to a completely different view and TabView as a union view of its subviews and substates.

Thanks!

[mbrandonw]

I don't think you would want to use this Destinations style for a tab view because it would clear out the state of all other tabs when a tab is selected.

Instead, I think it's better for a tab reducer to hold onto the state of all of its tabs:

struct TabFeature: ReducerProtocol {
  struct State {
    var tab1 = Tab1Feature.State()
    var tab2 = Tab2Feature.State()
    var tab3 = Tab3Feature.State()
  }
  enum Action {
    case tab1(Tab1Feature.Action)
    case tab2(Tab2Feature.Action)
    case tab3(Tab3Feature.Action)
  }
  var body: some ReducerProtocolOf<Self> {
    // ...
    Scope(state: \.tab1, action: Action.tab1) {
      Tab1Feature()
    }
    Scope(state: \.tab2, action: Action.tab2) {
      Tab2Feature()
    }
    Scope(state: \.tab3, action: Action.tab3) {
      Tab3Feature()
    }
  }