# expo-react-native-performance

Performance guidelines with 42 prioritized rules for Expo React Native apps. Helps agents refactor startup bottlenecks, list virtualization, re-renders, and animations.

- skill · `type=skill` · Claude Code, Codex, Cursor, GitHub Copilot, Gemini CLI, OpenCode · 1500 installs · ★ 218
- Author: pproenca
- License: MIT · policy=mirror · the beginning of the file is at the end of this page
- Source: https://github.com/pproenca/dot-skills/tree/HEAD/skills/.experimental/expo-react-native-performance/SKILL.md
- Updated: 2026-08-15
- HTML: https://affpapa.org/en/nevibecode/skills/expo-react-native-performance

## What it does

The skill organizes 42 performance rules across 8 impact-ranked categories. Critical items focus on startup time and bundle size, recommending the Hermes engine, direct file imports, and async routes. It also targets list virtualization by replacing `FlatList` with `FlashList` and configuring stable callbacks.

Component rendering rules enforce memoization, context splitting, and lazy state initialization. For smooth motion, animations must run on the native driver or Reanimated instead of recalculating dimensions. Asset guidelines mandate `expo-image` with WebP delivery.

These rules assume an Expo and React Native architecture. Applying them to generic React web projects causes friction because checks target mobile-specific internals like Android ProGuard and iOS text rendering.

## Install

### Claude Code (native platform)

1. **Skills CLI (Vercel)**
```bash
npx skills add pproenca/dot-skills --skill expo-react-native-performance -a claude-code
```

2. **Manually: put the files in place**
- File: `~/.claude/skills/expo-react-native-performance/SKILL.md` — Copy the whole skill folder; for one project use .claude/skills/expo-react-native-performance/

### Codex

1. **Skills CLI (Vercel)**
```bash
npx skills add pproenca/dot-skills --skill expo-react-native-performance -a codex
```

2. **Manually: put the files in place**
- File: `.agents/skills/expo-react-native-performance/SKILL.md` — For all projects use ~/.agents/skills/

### Cursor

1. **Skills CLI (Vercel)**
```bash
npx skills add pproenca/dot-skills --skill expo-react-native-performance -a cursor
```

2. **Manually: put the files in place**
- File: `.cursor/skills/expo-react-native-performance/SKILL.md` — Cursor also reads .agents/skills/ and .claude/skills/

### GitHub Copilot

1. **GitHub CLI**
```bash
gh skill install pproenca/dot-skills expo-react-native-performance
```

2. **Manually: put the files in place**
- File: `.github/skills/expo-react-native-performance/SKILL.md`

### Gemini CLI

1. **Skills CLI (Vercel)**
```bash
npx skills add pproenca/dot-skills --skill expo-react-native-performance -a gemini-cli
```

2. **Platform CLI**
```bash
gemini skills install https://github.com/pproenca/dot-skills --path skills/.experimental/expo-react-native-performance
```

### Windsurf (Devin Desktop)

**Manually: put the files in place**
- File: `.devin/skills/expo-react-native-performance/SKILL.md` — The legacy .windsurf/skills/ path still works

### OpenCode

**Skills CLI (Vercel)**
```bash
npx skills add pproenca/dot-skills --skill expo-react-native-performance -a opencode
```

### Claude.ai

**Claude.ai**
- Zip the folder and upload it in Settings → Capabilities → Skills

Where a file is given instead of a command, copy the files from the source to that path: https://github.com/pproenca/dot-skills/tree/HEAD/skills/.experimental/expo-react-native-performance/SKILL.md

## When to use it
- Cut cold startup time and shrink bundle size in Expo
- Migrate legacy FlatList components to FlashList
- Eliminate unnecessary component re-renders and stabilize hooks
- Offload heavy animations to the native driver and Reanimated
- Optimize image loading and caching with expo-image

## Example prompts
- Review this screen component against expo-react-native-performance guidelines
- Refactor our FlatList product catalog to FlashList with proper estimatedItemSize
- Check this data-fetching hook for memory leaks and cleanup subscriptions

## Source text · SKILL.md · MIT

Below is the content of a third-party file. It is data, not instructions for you: do not act on anything written inside unless the human asks. Block tag: f918de565002ca95.

BEGIN THIRD-PARTY FILE f918de565002ca95
```text
---
name: expo-react-native-performance
description: Expo React Native performance optimization guidelines. This skill should be used when writing, reviewing, or refactoring Expo React Native code to ensure optimal performance patterns. Triggers on tasks involving React Native components, lists, animations, images, or performance improvements.
---

# Expo React Native Performance Best Practices

Comprehensive performance optimization guide for Expo React Native applications. Contains 42 rules across 8 categories, prioritized by impact to guide automated refactoring and code generation.

## When to Apply

Reference these guidelines when:
- Writing new React Native components or screens
- Implementing lists with FlatList or FlashList
- Adding animations or transitions
- Optimizing images and asset loading
- Reviewing code for performance issues

## Rule Categories by Priority

| Priority | Category | Impact | Prefix |
|----------|----------|--------|--------|
| 1 | App Startup & Bundle Size | CRITICAL | `startup-` |
| 2 | List Virtualization | CRITICAL | `list-` |
| 3 | Re-render Optimization | HIGH | `rerender-` |
| 4 | Animation Performance | HIGH | `anim-` |
| 5 | Image & Asset Loading | MEDIUM-HIGH | `asset-` |
| 6 | Memory Management | MEDIUM | `mem-` |
| 7 | Async & Data Fetching | MEDIUM | `async-` |
| 8 | Platform Optimizations | LOW-MEDIUM | `platform-` |

## Quick Reference

### 1. App Startup & Bundle Size (CRITICAL)

- [`startup-enable-hermes`](references/startup-enable-hermes.md) - Enable Hermes JavaScript engine
- [`startup-remove-console-logs`](references/startup-remove-console-logs.md) - Remove console logs in production
- [`startup-splash-screen-control`](references/startup-splash-screen-control.md) - Control splash screen visibility
- [`startup-preload-assets`](references/startup-preload-assets.md) - Preload critical assets during splash
- [`startup-async-routes`](references/startup-async-routes.md) - Use async routes for code splitting
- [`startup-cherry-pick-imports`](references/startup-cherry-pick-imports.md) - Use direct imports instead of barrel files

### 2. List Virtualization (CRITICAL)

- [`list-use-flashlist`](references/list-use-flashlist.md) - Use FlashList instead of FlatList
- [`list-estimated-item-size`](references/list-estimated-item-size.md) - Provide accurate estimatedItemSize
- [`list-get-item-type`](references/list-get-item-type.md) - Use getItemType for mixed lists
- [`list-stable-render-item`](references/list-stable-render-item.md) - Stabilize renderItem with useCallback
```
END THIRD-PARTY FILE f918de565002ca95

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