import SwiftUI


struct ContentView: View {
    @ObservedObject var model = ContentViewModel()

    var body: some View {
        // change @ObservedObject value
        Text("ContentView")
            .frame(width: 100, height: 100)
            .background(Color.blue)
            .onTapGesture {
                model.isReady.toggle()
            }
        
        // change @ObservedObject value
        SaleView(model: model)
        
        
        // access @ObservedObject value
        Text(String(model.isReady))
    }
}


class ContentViewModel: ObservableObject {
    @Published var isReady = true
}


struct SaleView: View {
    @ObservedObject var model: ContentViewModel // can only declare, cannot initialize a new model which would be dependent.

    var body: some View {

        Text("change")
            .frame(width: 100, height:100)
            .background(Color.orange)
            .onTapGesture {
                model.isReady.toggle()
            }
    }
}