Programming Tutorials

  For years, SwiftUI data flow relied heavily on the Combine framework. We implemented   ObservableObject , marked properties with   @Published , and injected dependencies via   @StateObject   or   @EnvironmentObject . While functional, this approach introduced a hidden performance tax: over-invalidation. With Swift 5.9 and iOS 17, Apple introduced the Observation framework and the  @Observable  macro. This is not just syntactic sugar; it is a fundamental shift in how data dependency is tracked, moving from an  object-level  invalidation model to a  field-level  access tracking model. The Root Cause: The  objectWillChange  Bottleneck To understand why the migration is necessary, we must analyze the inefficiency of  ObservableObject . When you conform a class to  ObservableObject , the compiler synthesizes an  objectWillChange  publisher (unless you define one). Every time a property marked with...