swiftui-performance-audit

name	swiftui-performance-audit
description	Audit and improve SwiftUI runtime performance from code review and architecture. Use for requests to diagnose slow rendering, janky scrolling, high CPU/memory usage, excessive view updates, or layout thrash in SwiftUI apps, and to provide guidance for user-run Instruments profiling when code review alone is insufficient.

SwiftUI Performance Audit

Overview

Audit SwiftUI view performance end-to-end, from instrumentation and baselining to root-cause analysis and concrete remediation steps.

Workflow Decision Tree

• If the user provides code, start with "Code-First Review."
• If the user only describes symptoms, ask for minimal code/context, then do "Code-First Review."
• If code review is inconclusive, go to "Guide the User to Profile" and ask for a trace or screenshots.

1. Code-First Review

Collect:

• Target view/feature code.
• Data flow: state, environment, observable models.
• Symptoms and reproduction steps.

Ask the user to classify the symptom if possible — this steers the review and any later profiling request:

• CPU spike or battery drain
• Janky scrolling or dropped frames
• High memory or image pressure
• Hangs or unresponsive interactions
• Excessive or unexpectedly broad view updates

Focus on:

• View invalidation storms from broad state changes.
• Unstable identity in lists (id churn, UUID() per render).
• Top-level conditional view swapping (if/else returning different root branches).
• Heavy work in body (formatting, sorting, image decoding).
• Layout thrash (deep stacks, GeometryReader, preference chains).
• Large images without downsampling or resizing.