SwiftUI Observation (iOS 17+)

Overview

The @Observable macro (Observation framework) replaces ObservableObject/@Published. Views automatically track only the properties they actually read, so re-rendering becomes fine-grained instead of invalidating on every @Published change.

When to use

• New SwiftUI view models or app state on iOS 17+
• Migrating off ObservableObject, @Published, @StateObject, @ObservedObject, @EnvironmentObject
• Excess re-renders / performance from coarse @Published invalidation
• Two-way bindings to a reference-type model (@Bindable)

Property-wrapper map (old → new)