icecreamobserving.swift

import SwiftUI

struct ContentView: View {
    @State var viewModel = CoolViewModel()
    
    var body: some View {
        VStack {
            Menu {
                Picker("Ice Cream", selection: $viewModel.selectedIceCream) {
                    if let iceCreams = viewModel.iceCreams {
                        ForEach(iceCreams, id: \.self) { iceCream in
                            Text(iceCream)
                                .tag(iceCream)
                        }
                    }
                }
            } label: {
                Text("Choose")
            }
        }
        .onAppear {
            DispatchQueue.main.asyncAfter(deadline: .now() + .seconds(2)) {
                viewModel.selectedIceCream = "vanilla"
                viewModel.iceCreams = ["chocolate", "vanilla", "strawberry"]
            }
        }
    }
}

@Observable
class CoolViewModel {
    // These vars come in async, so aren't available right away
    var selectedIceCream: String?
    var iceCreams: [String]?
}