swift-optimise

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Apple Swift/SwiftUI Performance Optimization Best Practices

Apple Swift/SwiftUI性能优化最佳实践

Comprehensive guide for Swift and SwiftUI performance optimization. Contains 19 rules across 3 categories covering modern concurrency, render performance, and animation performance. Targets iOS 26 / Swift 6.2 with @Observable and Swift 6 strict concurrency.

这是一份关于Swift和SwiftUI性能优化的综合指南，包含3个类别共19条规则，覆盖现代并发、渲染性能和动画性能三大领域。针对iOS 26 / Swift 6.2版本，适配@Observable特性及Swift 6严格并发模式。

Clinic Architecture Contract (iOS 26 / Swift 6.2)

诊所架构约定（iOS 26 / Swift 6.2）

All guidance in this skill assumes the clinic modular MVVM-C architecture:

Feature modules import
```
Domain
```
+
```
DesignSystem
```
only (never
```
Data
```
, never sibling features)
App target is the convergence point and owns
```
DependencyContainer
```
, concrete coordinators, and Route Shell wiring
```
Domain
```
stays pure Swift and defines models plus repository,
```
*Coordinating
```
,
```
ErrorRouting
```
, and
```
AppError
```
contracts
```
Data
```
owns SwiftData/network/sync/retry/background I/O and implements Domain protocols
Read/write flow defaults to stale-while-revalidate reads and optimistic queued writes
ViewModels call repository protocols directly (no default use-case/interactor layer)

本指南中的所有内容均基于诊所模块化MVVM-C架构：

Feature模块仅导入
```
Domain
```
+
```
DesignSystem
```
（绝不导入
```
Data
```
或同级Feature模块）
App目标作为汇聚点，拥有
```
DependencyContainer
```
、具体协调器及路由壳层的配置
```
Domain
```
层为纯Swift实现，定义模型以及repository、
```
*Coordinating
```
、
```
ErrorRouting
```
和
```
AppError
```
协议
```
Data
```
层负责SwiftData/网络/同步/重试/后台I/O操作，并实现Domain层定义的协议
默认读写流程采用 stale-while-revalidate 读取策略和乐观队列写入策略
ViewModel直接调用repository协议（默认不使用用例/交互器层）

When to Apply

适用场景

Reference these guidelines when:

Migrating to Swift 6 strict concurrency (Sendable, actor isolation)
Replacing Combine publishers with async/await
Implementing @MainActor isolation and actor-based concurrency
Decomposing views to reduce state invalidation blast radius
Optimizing scroll and render performance with lazy containers
Using Canvas/TimelineView for high-performance rendering
Profiling with SwiftUI Instruments before optimizing
Building performant spring animations and transitions

在以下场景中可参考本指南：

迁移至Swift 6严格并发模式（Sendable、actor隔离）
使用async/await替代Combine发布者
实现@MainActor隔离及基于actor的并发机制
拆分视图以缩小状态失效影响范围
使用懒加载容器优化滚动与渲染性能
采用Canvas/TimelineView实现高性能渲染
优化前使用SwiftUI Instruments进行性能分析
构建高性能弹簧动画与转场效果

Rule Categories by Priority

按优先级划分的规则类别

Priority	Category	Impact	Prefix
1	Concurrency & Async	CRITICAL	`conc-`
2	Render & Scroll Performance	HIGH	`perf-`
3	Animation Performance	MEDIUM	`anim-`

优先级	类别	影响级别	前缀
1	并发与异步	关键	`conc-`
2	渲染与滚动性能	高	`perf-`
3	动画性能	中	`anim-`

Quick Reference

快速参考

1. Concurrency & Async (CRITICAL)

1. 并发与异步（关键）

```
conc-combine-to-async
```
- Replace Combine publishers with async/await
```
conc-mainactor-isolation
```
- Use @MainActor instead of DispatchQueue.main
```
conc-swift6-sendable
```
- Adopt Sendable and Swift 6 strict concurrency
```
conc-task-id-pattern
```
- Use .task(id:) for reactive data loading
```
conc-actor-for-shared-state
```
- Replace lock-based shared state with actors
```
conc-asyncsequence-streams
```
- Replace NotificationCenter observers with AsyncSequence

```
conc-combine-to-async
```
- 使用async/await替代Combine发布者
```
conc-mainactor-isolation
```
- 使用@MainActor替代DispatchQueue.main
```
conc-swift6-sendable
```
- 适配Sendable及Swift 6严格并发模式
```
conc-task-id-pattern
```
- 使用.task(id:)实现响应式数据加载
```
conc-actor-for-shared-state
```
- 用actor替代基于锁的共享状态管理
```
conc-asyncsequence-streams
```
- 使用AsyncSequence替代NotificationCenter观察者

2. Render & Scroll Performance (HIGH)

2. 渲染与滚动性能（高）

```
perf-view-decomposition
```
- Decompose views to limit state invalidation blast radius
```
perf-instruments-profiling
```
- Profile with SwiftUI Instruments before optimizing
```
perf-lazy-containers
```
- Use lazy containers for large collections
```
perf-canvas-timeline
```
- Use Canvas and TimelineView for high-performance rendering
```
perf-drawinggroup
```
- Use drawingGroup for complex graphics
```
perf-equatable-views
```
- Add Equatable conformance to prevent spurious redraws
```
perf-task-modifier
```
- Use .task modifier instead of .onAppear for async work
```
perf-async-image
```
- Use AsyncImage with caching strategy for remote images

```
perf-view-decomposition
```
- 拆分视图以缩小状态失效影响范围
```
perf-instruments-profiling
```
- 优化前使用SwiftUI Instruments进行性能分析
```
perf-lazy-containers
```
- 对大型集合使用懒加载容器
```
perf-canvas-timeline
```
- 采用Canvas和TimelineView实现高性能渲染
```
perf-drawinggroup
```
- 使用drawingGroup处理复杂图形
```
perf-equatable-views
```
- 添加Equatable一致性以避免不必要的重绘
```
perf-task-modifier
```
- 使用.task修饰符替代.onAppear执行异步任务
```
perf-async-image
```
- 结合缓存策略使用AsyncImage加载远程图片

3. Animation Performance (MEDIUM)

3. 动画性能（中）

```
anim-spring
```
- Use spring animations as default
```
anim-matchedgeometry
```
- Use matchedGeometryEffect for shared transitions
```
anim-gesture-driven
```
- Make animations gesture-driven
```
anim-with-animation
```
- Use withAnimation for state-driven transitions
```
anim-transition-effects
```
- Apply transition effects for view insertion and removal

```
anim-spring
```
- 优先使用弹簧动画
```
anim-matchedgeometry
```
- 使用matchedGeometryEffect实现共享转场
```
anim-gesture-driven
```
- 实现手势驱动的动画
```
anim-with-animation
```
- 使用withAnimation处理状态驱动的转场
```
anim-transition-effects
```
- 为视图的插入和移除应用转场效果

How to Use

使用方法

Read individual reference files for detailed explanations and code examples:

Section definitions - Category structure and impact levels
Rule template - Template for adding new rules

如需详细说明及代码示例，请阅读各参考文件：

章节定义 - 类别结构与影响级别说明
规则模板 - 新增规则的模板

Reference Files

参考文件

File	Description
references/_sections.md	Category definitions and ordering
assets/templates/_template.md	Template for new rules

文件	描述
references/_sections.md	类别定义与排序说明
assets/templates/_template.md	新增规则模板