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A Deep Dive Into Observation: A New Way to Boost SwiftUI Performance
The Observation framework should reduce unnecessary updates in SwiftUI views, improving the performance of SwiftUI apps
At WWDC 2023, Apple introduced a new member of the Swift standard library — the Observation framework. Its appearance is expected to alleviate the long-standing issue of unnecessary updates to SwiftUI views for developers.
This article will comprehensively and thoroughly explore the Observation framework in a Q&A format, including its reasons for creation, usage methods, workings, and precautions.
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The Need for Observation Framework
Before Swift 5.9, Apple did not provide developers with a unified and efficient mechanism for observing changes to reference type properties. KVO is limited to use by NSObject subclasses, Combine cannot provide precise observation at the property level, and neither can achieve cross-platform support.
In addition, in SwiftUI, the source of truth for reference type data sources is implemented using the ObservableObject protocol based on the Combine framework. This leads to a large number of unnecessary view refreshes in SwiftUI, which affects the performance of SwiftUI applications.
To address these limitations, the Observation framework was introduced in Swift 5.9. Compared to existing KVO and Combine, it has the following advantages:
- It is applicable to all Swift reference types, not just NSObject subclasses, and provides…
