bug_tokamak.swift

import TokamakShim
import JavaScriptKit

public let window = JSObject.global.window.object!
public let location = JSObject.global.location.object!

struct TokamakApp: App {
    var body: some Scene {
        WindowGroup("Tokamak App") {
            ContentView()
        }
    }
}

struct Menu: View {

    var body: some View {
       VStack() {
           Button("Add") { 
               navigate(to: "Add")
           }.padding()
           
           Button("List") { 
               navigate(to: "List")
           }.padding()
       }
    }
}


struct Table: View {

    public var body: some View {
     VStack {
        ForEach((1...10).reversed(), id: \.self) {
                Text("\($0)…")
            }
     }.background(Color.yellow)
    }
}

struct Add: View {
    public var body: some View {
        VStack {
            Text("Add")
        }.background(Color.red)

    }
}


func navigate(to: String) {
    location.hash = JSValue(stringLiteral: to)
}


public final class HashState: ObservableObject {
   var onHashChange: JSClosure!

   @Published var currentHash = location.hash.string!

   init() {
     let onHashChange = JSClosure { [weak self] _ in
       self?.currentHash = location.hash.string!
     }

     window.onhashchange = .function(onHashChange)
     self.onHashChange = onHashChange
   }

   deinit {
     window.onhashchange = .undefined
     onHashChange.release()
   }
 }

struct ContentView: View {
    @StateObject private var hashState = HashState()

    var body: some View {
        HStack {
          Menu()
          Text("begin")
          switch(hashState.currentHash) {
              case "#List": Table()
              case "#Add": Add()
              default: Text("default") 
          }
          Text("end")
        }
    }
}


// @main attribute is not supported in SwiftPM apps.
// See https://bugs.swift.org/browse/SR-12683 for more details.
TokamakApp.main()