/swiftui-patterns

Migration Checklist

When updating legacy SwiftUI code to iOS 17+:

• Replace ObservableObject with @Observable
• Remove all @Published (regular properties auto-publish)
• Replace @StateObject with @State
• Replace @ObservedObject with @Bindable
• Replace environmentObject(_:) with environment(_:)
• Replace @EnvironmentObject with @Environment(Type.self)
• Update onChange(of:perform:) to onChange(of:initial:_:)
• Replace .onAppear { Task {} } with .task

Before & After Example

Before (iOS 16)

class UserProfileModel: ObservableObject {
    @Published var name: String = ""
    @Published var email: String = ""
}

struct ProfileView: View {
    @StateObject private var model = UserProfileModel()

    var body: some View {
        TextField("Name", text: $model.name)
            .onAppear {
                Task {
                    await model.load()
                }
            }
    }
}

After (iOS 17+)

@Observable
class UserProfileModel {
    var name: String = ""
    var email: String = ""
}

struct ProfileView: View {
    @State private var model = UserProfileModel()

    var body: some View {
        TextField("Name", text: $model.name)
            .task {
                await model.load()
            }
    }
}