I have an app in which the data model is @Observable, and views see it through @Environment(dataModel.self) private var dataModel. Since there are a large number of views, only some of which may need to be redrawn at a given time, I believe that @Observable is more efficient at run time than @Published and @ObservedObject I’ve been trying to make the app document based. Although I started using SwiftData, it has trouble with Codable, and a long thread in the Developer forum suggests that SwiftData does not support the Undo manager - and in any event, simple JSON serialization is all that this app requires. Unfortunately, ReferenceFileDocument inherits from ObservableObject, which seems to not play nice with @Observable. I’d like to keep using @Observable, but haven’t been able to figure out how. When I deserialize a JSON ReferenceFileDocument, I can’t seem to connect it to an @Observable class instance and to let the various views and view models know where to find and update it. I’d appreciate advice on how to implement document persistence in this app. Also, the default behaviour of DoumentGroup provides a nice menu to, another things, rename a new file to something other than Untitled xx, but it doesn’t appear to work (there is an extensive thread on the Developer website discussing this issue). Is there a solution to this problem? Thanks for any help you can offer.

Let's say you have a protocol that can work with both classes and structs but you want to have a uniform UI to make edits. What is the recommended way to have one view that will take both? App import SwiftUI @main struct ObservationTesterApp: App { var body: some Scene { WindowGroup { ContentView(existence: Existence()) } } } Types import Foundation protocol Dateable { var timestamp:Date { get set } } struct Arrival:Dateable { var timestamp:Date } @Observable class Existence:Dateable { var timestamp:Date init(timestamp: Date) { self.timestamp = timestamp } } extension Existence { convenience init() { self.init(timestamp: Date()) } } ContentView, etc // // ContentView.swift // ObservationTester // // import SwiftUI struct EditDateableView<TimedThing:Dateable>:View { @Binding var timed:TimedThing //note that this currently JUST a date picker //but it's possible the protocol would have more var body:some View { DatePicker("Time To Change", selection: $timed.timestamp) } } #Preview { @Previewable @State var tt = Arrival(timestamp: Date()) EditDateableView<Arrival>(timed: $tt) } struct ContentView: View { @State var arrival = Arrival(timestamp: Date()) @Bindable var existence:Existence var body: some View { //this work around also not allowed. "self is immutable" // let existBinding = Binding<Existence>(get: { existence }, set: { existence = $0 }) VStack { EditDateableView(timed: $arrival) //a Binding cant take a Bindable //EditDateableView<Existence>(timed: $existence) } .padding() } } #Preview { ContentView(existence: Existence()) }