Performance Optimizer

Instructions

Optimize Leavn app performance:

1. Find main thread operations:

   • Search for regex in View body
   • Find CGContext/UIGraphicsImageRenderer in Views
   • Look for DispatchQueue.main.async chains
   • Check for heavy computation in computed properties

2. Fix patterns:

   // BEFORE - Main thread blocking
   let result = expensiveRegex()
   
   // AFTER - Background
   Task.detached {
       let result = await expensiveWork()
       await MainActor.run { updateUI(result) }
   }
   

3. Add lazy loading:

   • Use .onAppear with viewport tracking
   • LazyVStack for long lists
   • Defer AI transformations until visible

4. Optimize lookups:

   // BEFORE - O(n)
   array.contains { $0.id == id }
   
   // AFTER - O(1)
   private lazy var idSet = Set(array.map(\.id))
   idSet.contains(id)
   

5. Cache computations:

   • Move from View to ViewModel
   • Invalidate cache on data change
   • Use didSet observers

Use this skill when: UI is laggy, scrolling stutters, app feels slow, CPU usage high