//Router store
  @Perception.Bindable private var store: Store<[Route<Screen>], RouterAction<ID, Screen, ScreenAction>>

//Router scoping function
  func scopedStore(index: Int, screen: Screen) -> Store<Screen, ScreenAction> {
    var screen = screen
    let id = identifier(screen, index)
    return store.scope(
      id: store.id(state: \.[index], action: \.[id: id]),
      state: ToState {
        screen = $0[safe: index]?.screen ?? screen
        return screen
      },
      action: {
        .routeAction(id: id, action: $0)
      },
      isInvalid: { !$0.indices.contains(index) }
    )
  }

@_spi(Internals)
  public func scope<ChildState, ChildAction>(
    id: ScopeID<State, Action>?,
    state: ToState<State, ChildState>,
    action fromChildAction: @escaping (ChildAction) -> Action,
    isInvalid: ((State) -> Bool)?
  ) -> Store<ChildState, ChildAction> 

@_spi(Internals)
extension Store {
  public func scope<ChildState, ChildAction>(
    cached: ChildState,
    keypath: KeyPath<State, ChildState?>,
    action: CaseKeyPath<Action, ChildAction>
  ) -> Store<ChildState, ChildAction> {
    let id = self.id(state: keypath, action: action)
    @MainActor
    func open(
      _ core: some Core<State, Action>
    ) -> any Core<ChildState, ChildAction> {
      IfLetCore(
        base: core,
        cachedState: cached,
        stateKeyPath:keypath,
        actionKeyPath: action
      )
    }
    return self.scope(id: id, childCore: open(self.core))
  }
}