Why is the navigationDestination with the binding not updating properly? - swiftui

Question

Why is the binding not updating the array and the PatientView title in the ContentView?
I use the ForEach that takes a binding and the navigationDestination then passes that binding to the child view.
import SwiftUI
struct PatientView: View {
#Binding var patient: Patient
var body: some View {
Section("Name") {
TextField("Name", text: $patient.name)
.textFieldStyle(.roundedBorder)
}
Spacer()
.navigationTitle(patient.name)
}
}
protocol BlankInit {
init()
}
extension View {
func binding<V>(id: V.ID, array: Binding<[V]>) -> Binding<V> where V: Identifiable {
if let ret = array.first(where: { $0.id == id}) {
return ret
} else {
fatalError()
}
}
}
extension Binding : Hashable, Equatable where Value: Identifiable, Value: Equatable, Value: Hashable {
public static func == (lhs: Binding<Value>, rhs: Binding<Value>) -> Bool {
lhs.wrappedValue == rhs.wrappedValue
}
public func hash(into hasher: inout Hasher) {
hasher.combine("Binding")
hasher.combine(self.wrappedValue)
}
}
struct Patient: Hashable, Equatable, Identifiable, BlankInit {
var id: UUID = UUID()
var name: String = ""
var age: UInt8 = 0
init(_ name: String, age: UInt8 = 0) {
self.name = name
self.age = 0
self.id = UUID()
}
init() {
self.name = ""
self.age = 0
self.id = UUID()
}
static func == (lhs: Patient, rhs: Patient) -> Bool {
lhs.id == rhs.id && lhs.name == rhs.name && lhs.age == rhs.age
}
}
struct ContentView: View {
#StateObject var appData: AppData = AppData()
var body: some View {
NavigationStack(path: $appData.path) {
List {
ForEach($appData.patients) { $pt in
NavigationLink(pt.name, value: $pt)
}
}
.navigationDestination(for: Binding<Patient>.self) { item in
PatientView(patient: item)
}
.navigationTitle("Patients")
}
.environmentObject(appData)
.padding()
}
}
class AppData: ObservableObject {
#Published var path = NavigationPath()
#Published var patients = [Patient]()
init() {
patients.append(Patient("Smith"))
patients.append(Patient("Jones"))
patients.append(Patient("DeCaro"))
}
}
#main
struct TestAppApp: App {
var body: some Scene {
WindowGroup {
ContentView() //.environmentObject(AppData())
}
}
}
It works fine if I do the following:
struct ContentView: View {
#StateObject var appData: AppData = AppData()
var body: some View {
NavigationStack(path: $appData.path) {
List {
ForEach(appData.patients) { pt in
NavigationLink(pt.name, value: pt)
}
}
.navigationDestination(for: Patient.self) { item in
let binding = binding(id: item.id, array: $appData.patients)
PatientView(patient: binding)
}
.navigationTitle("Patients")
}
.environmentObject(appData)
.padding()
}
}
It seems more 'elegant' and less kludgy to be able to do the Binding version????