axiom-swiftui-performance

# SwiftUI Performance Optimization

## When to Use This Skill

Use when:
- App feels less responsive (hitches, hangs, delayed scrolling)
- Animations pause or jump during execution
- Scrolling performance is poor
- Profiling reveals SwiftUI is the bottleneck
- View bodies are taking too long to run
- Views are updating more frequently than necessary
- Need to understand cause-and-effect of SwiftUI updates

## Example Prompts

These are real questions developers ask that this skill is designed to answer:

#### 1. "My app has janky scrolling and animations are stuttering. How do I figure out if SwiftUI is the cause?"
→ The skill shows how to use the new SwiftUI Instrument in Instruments 26 to identify if SwiftUI is the bottleneck vs other layers

#### 2. "I'm using the new SwiftUI Instrument and I see orange/red bars showing long updates. How do I know what's causing them?"
→ The skill covers the Cause & Effect Graph patterns that show data flow through your app and which state changes trigger expensive updates

#### 3. "Some views are updating way too often even though their data hasn't changed. How do I find which views are the problem?"
→ The skill demonstrates unnecessary update detection and Identity troubleshooting with the visual timeline

#### 4. "I have large data structures and complex view hierarchies. How do I optimize them for SwiftUI performance?"
→ The skill covers performance patterns: breaking down view hierarchies, minimizing body complexity, and using the @Sendable optimization checklist

#### 5. "We have a performance deadline and I need to understand what's slow in SwiftUI. What are the critical metrics?"
→ The skill provides the decision tree for prioritizing optimizations and understands pressure scenarios with professional guidance for trade-offs

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## Overview

**Core Principle**: Ensure your view bodies update quickly and only when needed to achieve great SwiftUI performance.

**NEW in WWDC 2025**: Next-generation SwiftUI instrument in Ins