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name: vercel-react-native-skills description: React Native and Expo best practices for building performant mobile apps. Use when building React Native components, optimizing list performance, implementing animations, or working with native modules. Triggers on tasks involving React Native, Expo, mobile performance, or native platform APIs. license: MIT metadata: author: vercel version: '1.0.0'

React Native Skills

Comprehensive best practices for React Native and Expo applications. Contains rules across multiple categories covering performance, animations, UI patterns, and platform-specific optimizations.

When to Apply

Reference these guidelines when:

• Building React Native or Expo apps
• Optimizing list and scroll performance
• Implementing animations with Reanimated
• Working with images and media
• Configuring native modules or fonts
• Structuring monorepo projects with native dependencies

Rule Categories by Priority

Priority	Category	Impact	Prefix
1	List Performance	CRITICAL	list-performance-
2	Animation	HIGH	animation-
3	UI Patterns	HIGH	ui-
4	State Management	MEDIUM	react-state-
5	Rendering	MEDIUM	rendering-
6	Monorepo	MEDIUM	monorepo-
7	Configuration	LOW	fonts-, imports-

Quick Reference

1. List Performance (CRITICAL)

• list-performance-virtualize - Use FlashList for large lists
• list-performance-item-memo - Memoize list item components
• list-performance-callbacks - Stabilize callback references
• list-performance-inline-objects - Avoid inline style objects
• list-performance-function-references - Extract functions outside render
• list-performance-images - Optimize images in lists
• list-performance-item-expensive - Move expensive work outside items

2. Animation (HIGH)

• animation-gpu-properties - Animate only transform and opacity
• animation-derived-value - Use useDerivedValue for computed animations
• animation-gesture-detector-press - Use Gesture.Tap instead of Pressable

3. UI Patterns (HIGH)

• ui-expo-image - Use expo-image for all images
• ui-image-gallery - Use Galeria for image lightboxes
• ui-pressable - Use Pressable over TouchableOpacity
• ui-safe-area-scroll - Handle safe areas in ScrollViews
• ui-scrollview-content-inset - Use contentInset for headers
• ui-menus - Use native context menus
• ui-native-modals - Use native modals when possible
• ui-measure-views - Use onLayout, not measure()
• ui-styling - Use StyleSheet.create or Nativewind

4. State Management (MEDIUM)

• react-state-minimize - Minimize state subscriptions
• react-state-dispatcher - Use dispatcher pattern for callbacks
• react-state-fallback - Show fallback on first render
• react-compiler-destructure-functions - Destructure for React Compiler
• react-compiler-reanimated-shared-values - Handle shared values with compiler

5. Rendering (MEDIUM)

• rendering-text-in-text-component - Wrap text in Text components
• rendering-no-falsy-and - Avoid falsy && for conditional rendering

6. Monorepo (MEDIUM)

• monorepo-native-deps-in-app - Keep native dependencies in app package
• monorepo-single-dependency-versions - Use single versions across packages

7. Configuration (LOW)

• fonts-config-plugin - Use config plugins for custom fonts
• imports-design-system-folder - Organize design system imports
• js-hoist-intl - Hoist Intl object creation

How to Use

Read individual rule files for detailed explanations and code examples:

rules/list-performance-virtualize.md
rules/animation-gpu-properties.md

Each rule file contains:

• Brief explanation of why it matters
• Incorrect code example with explanation
• Correct code example with explanation
• Additional context and references

Full Compiled Document

For the complete guide with all rules expanded: AGENTS.md

⚠️ よくある落とし穴

• FlatListで大量リストを描画してパフォーマンスが悪化する: FlatListはリサイクルが不完全。大量データにはFlashListを使い、estimatedItemSize を必ず指定する
• リストアイテム内でインラインスタイルやインライン関数を使う: style={{ marginTop: 10 }} や onPress={() => ...} は毎レンダリングで新しい参照を生成し、アイテムのメモ化が無効になる。StyleSheet.createと外部関数（またはuseCallback）を使う
• transform/opacity以外のプロパティをアニメーションする: layoutプロパティ（width, height, marginなど）のアニメーションはJSスレッドを経由し、フレームドロップを引き起こす。Reanimatedで transform と opacity のみをアニメーションする
• TouchableOpacityを使い続ける: TouchableOpacityは非推奨。Pressable（またはGesture.Tap）に移行する。特にリストアイテムではGesture.Tapの方がパフォーマンスが良い