Observe SwiftData Changes Without Rebuilding Your Own Diff Engine

This article explains how to efficiently observe changes in SwiftData without building a custom diff engine. It covers new APIs introduced at WWDC26, including sectioned @Query(sectionBy:) for grouped results in SwiftUI, ResultsObserver for observation in non-view code, and HistoryObserver for detecting persistent history transactions. The article provides practical examples with a Trip model, discusses the use of @Attribute(.codable) for types like MKMapItem.Identifier, and notes SDK requirements (iOS 27 and macOS 27). It emphasizes avoiding manual array diffs and leveraging SwiftData's built-in observation mechanisms.