Observable vs observer

The terms "observable" and "observer" are often used in the context of software design patterns, particularly in the Observer pattern. However, in the context of WWDC sessions, these terms can also relate to specific features and functionalities in Swift and AVFoundation.

Observable in Swift

In Swift, the concept of observability is crucial for understanding and troubleshooting services. Observability consists of three main pillars: logging, metrics, and tracing. These help in understanding the behavior and health of services. For example, in the session Explore the Swift on Server ecosystem, observability is discussed in the context of adding additional logging, metrics, and tracing to services to help with troubleshooting.

Observer in AVFoundation

In AVFoundation, the observer pattern is used to handle events. The session Discover media performance metrics in AVFoundation discusses how AVFoundation interfaces support publishing events and conform to the AV metric event stream publisher protocol. This allows apps to subscribe to specific events they are interested in, effectively acting as observers.

Observable Object in SwiftUI

In SwiftUI, an ObservableObject is a class that conforms to the ObservableObject protocol, which allows SwiftUI views to automatically update when the data changes. This is discussed in the session Migrate your app to Swift 6, where the importance of marking objects as observable for proper data handling and avoiding data races is highlighted.

Summary of Relevant Sessions

These sessions provide a comprehensive overview of how observability and observer patterns are implemented and utilized in Swift and AVFoundation.