Vanilla SwiftUI Core Data edit

PostEdit.swift

import SwiftUI
import CoreData

struct PostEditView: View {
   
    @ObservedObject var post: Post
    @Environment(\.managedObjectContext) var moc
    @State var hasChanges: Bool = false
    
    var body: some View {
        Form {
            TextField("Title", text: $post.title.optionalBinding)

            TextEditor(text: $post.content.optionalBinding)
                .frame(height: 120.0)

            TextField("Excerpt", text: $post.excerpt.optionalBinding)

            HStack {
                Toggle(isOn: $post.publishedAt.optionalBinding(falseValue: nil)) {
                    HStack {
                        Text("Published")
                        if let at = post.publishedAt {
                            Spacer()
                            Text(at,format: Date.FormatStyle.dateTime)
                                .foregroundStyle(.secondary)
                        }
                    }
                }
            }

            if let createdAt = post.createdAt {
                LabeledContent("Created") {
                    Text(createdAt,format: Date.FormatStyle.dateTime)
                }
            }
        }
        .toolbar {
            ToolbarItemGroup(placement: .confirmationAction) {
                Button {
                   updatePost()
                } label: {
                    Text(post.createdAt != nil ? "Update" : "Save")
                }
                .disabled(!hasChanges)
            }
        }
        .onChange(of: post.hasPersistentChangedValues ) { newValue in
            updateHasChanges()
        }
        .onAppear() {
            updateHasChanges()
        }
    }
    
    func updateHasChanges() {
        hasChanges = post.hasPersistentChangedValues
    }
        
    func updatePost() {
        do {
            try moc.save()
            updateHasChanges()
        } catch {
            print(">>>>> Error saving Post")
        }
    }
}

struct PostEditView_Previews: PreviewProvider {
    
    @Environment(\.managedObjectContext) var moc
    static var previews: some View {
        NavigationView {
            PostEditView(post: Post(context: PersistenceController.preview.container.viewContext))
                .environment(\.managedObjectContext, PersistenceController.preview.container.viewContext)
        }
    }
}

// String? <-> String
extension Binding where Value == String? {
    var optionalBinding: Binding<String> {
        .init(
            get: {
                self.wrappedValue ?? ""
            }, set: {
                self.wrappedValue = $0.isEmpty ? nil : $0
            }
        )
    }
}

// Date? <-> String
extension Binding where Value == Date? {
    func optionalBinding(formatter: DateFormatter) -> Binding<String> {
        .init(
            get: {
                self.wrappedValue != nil ? formatter.string(from: self.wrappedValue!) : ""
            }, set: {
                self.wrappedValue = $0.isEmpty ? nil : formatter.date(from: $0)
            }
        )
    }
}

// PublishedAt? <-> Bool
extension Binding where Value == Date? {
    func optionalBinding(falseValue: Date? = nil) -> Binding<Bool> {
        .init(
            get: {
                return self.wrappedValue != nil
            }, set: { _ in
                self.wrappedValue = self.wrappedValue == nil ? .now : falseValue
            }
        )
    }
}