มาโคร @Observable

A plain model class holds data, but SwiftUI will not redraw when that data changes. We need to make the class observable.

The @Observable macro marks a class so SwiftUI watches its properties and refreshes any view that reads them. ✨

A macro generates extra code for you at compile time, so one short attribute adds all the change-tracking plumbing.

The macro lives in the Observation framework, so add an import at the top of the file before you use it.

With @Observable you mark plain stored properties. No per-property wrapper is required for SwiftUI to track them.

SwiftUI only refreshes for the properties a view actually reads in its body, so unused values cost you nothing.

When you change a tracked property, every view that reads it is automatically scheduled to redraw.

A computed property built from tracked values also updates views, since reading it reads its inputs.

Tracking is granular: changing one property only refreshes views that read that property, not the whole screen.

@Observable is the modern replacement for the older ObservableObject plus @Published pattern, with far less boilerplate.

Mark a value with @ObservationIgnored when it should not trigger updates, like a cache or internal scratch value.

Time to check your grip on @Observable.

You made a model @Observable, so SwiftUI tracks the properties your views read and redraws them precisely when those values change. 🎉