swiftui-performance

Diagnose SwiftUI rendering issues and optimize view performance.

Updated Apr 30, 2026
One-click install
npx skills add https://github.com/onymchat/onym-ios --skill swiftui-performance-onymchat
Or copy as Structured Prompt for Agent
Please help me install this Agent Skill.
Skill: swiftui-performance
Source: https://github.com/onymchat/onym-ios/tree/main/.claude/skills/swiftui-performance
Command: npx skills add https://github.com/onymchat/onym-ios --skill swiftui-performance-onymchat

SYSTEM DOCUMENTATION & REQUIREMENTS

💡 This Skill includes references (resource) components.

What problem does it solve?

SwiftUI apps often suffer from slow frames, jank, and excessive re-renders due to expensive view bodies, unstable identity in lists, and broad dependency updates. This Skill provides a structured approach to measure, diagnose, and remediate these pitfalls to deliver smoother UI.

Core Features & Use Cases

  • Instrument SwiftUI performance with the official timeline, Time Profiler, and related diagnostics to locate hot updates.
  • Narrow dependencies and stabilize identity to reduce unnecessary re-evaluation and diff churn.
  • Precompute and cache expensive presentation data, and split large models into focused subviews to minimize update fan-out.
  • Use Case: A scrolling list that jitters due to frequent updates can be improved by isolating state and avoiding expensive work in body.

Quick Start

Profile a representative interaction with the SwiftUI Instrument to baseline performance and identify hot updates.

Frequently Asked Questions about swiftui-performance

High-intent search queries and answers about installing and using this skill.

FAQPage Schema
Why does my SwiftUI list jitter when scrolling and how do I fix it?

SwiftUI list jitter often stems from broad dependency updates and unstable identity causing excessive re-renders. You fix it by isolating state, precomputing expensive presentation data, and splitting large models into focused subviews to minimize update fan-out.

How do I profile SwiftUI rendering to find slow frames?

Profile SwiftUI rendering by using the official SwiftUI Instrument timeline and Time Profiler to baseline a representative interaction. This locates hot updates and identifies expensive view bodies or excessive re-evaluation causing frame drops.

What is the best way to reduce unnecessary re-renders in SwiftUI?

The best way to reduce unnecessary SwiftUI re-renders is narrowing dependency scoping and stabilizing identity in lists. This prevents broad dependency updates and diff churn, stopping the system from re-evaluating unchanged views.

Does using AnyView cause SwiftUI performance issues?

Yes, using AnyView causes SwiftUI performance issues because it erases view identity and prevents diffing optimizations. Avoid AnyView and instead use precise dependency scoping and stable identities to maintain efficient rendering.

Can I optimize heavy SwiftUI body computation for release-device profiling?

Yes, you can optimize heavy SwiftUI body computation for release-device profiling by precomputing and caching expensive presentation data. This avoids performing expensive work directly in the view body during scrolling interactions.

When should I split large models into subviews in SwiftUI?

You should split large models into focused subviews in SwiftUI when a screen experiences high frame drops or jank. This minimizes update fan-out by ensuring only the affected subview re-renders instead of the entire model.