Article_007 https://nalexn.github.io/swiftui-observableobject/

Article_007_ObservableObject_06.swift

struct ContentView: View {
    
    // The local view's state encapsulated in one container:
    @State private var state = ViewState()
    
    // The app's state injection
    @Environment(\.injected) private var injected: AppState.Injection
    
    var body: some View {
        Text("Value: \(state.value)")
            .onReceive(stateUpdate) { self.state = $0 }
    }
    
    // The state update filtering
    private var stateUpdate: AnyPublisher<ViewState, Never> {
        injected.appState.map { $0.viewState }
            .removeDuplicates().eraseToAnyPublisher()
    }
}

// Container for the local view state encapsulation
private extension ContentView {
    struct ViewState: Equatable {
        var value: Int = 0
    }
}

// Convenient mapping from AppState to ViewState
private extension AppState {
    var viewState: ContentView.ViewState {
        return .init(value: value1)
    }
}