expo-development

React Native & Expo Development Rules

Command Usage

Workspace Commands

• ALWAYS use pnpm dev instead of expo start directly
• ALWAYS use pnpm ios for iOS development (includes Xcode version check)
• ALWAYS use pnpm android for Android development
• ALWAYS use pnpm web for web development
• ALWAYS use pnpm web:build for production web builds
• NEVER run expo start directly - use workspace commands

EAS Build Commands

• Development builds: pnpm eas:build:dev:* (simulator, device, local)
• Staging builds: pnpm eas:build:staging:*
• Submit builds: pnpm eas:submit:*
• Update builds: pnpm eas:update:*
• Platform-specific: Add :ios or :android suffix

Server Assumptions

• ASSUME Expo dev server is running on http://localhost:8081
• ASSUME Metro bundler is running and watching for changes
• DO NOT start Expo servers unless explicitly requested

Development Workflow

• Test on actual devices when possible
• Use Expo Go app for quick testing
• Test on both iOS and Android when making platform-specific changes
• Use pnpm prebuild before native builds
• Check Xcode version automatically with pnpm ios

Platform-Specific Files

React Native supports platform-specific file extensions:

• .native.tsx - React Native specific implementations
• .ios.tsx - iOS specific implementations
• .android.tsx - Android specific implementations
• .web.tsx - Web specific implementations

Key Generation

Security Requirements

• ALWAYS use randomUUID() from expo-crypto for generating unique keys and identifiers
• NEVER use Math.random() or other insecure methods for key generation
• IMPORT from expo-crypto when generating UUIDs for React keys, database IDs, or any unique identifiers

// ✅ Good - using expo-crypto for key generation
import { randomUUID } from 'expo-crypto';

const generateKey = () => randomUUID();
const itemKey = randomUUID();

// ❌ Bad - using insecure methods
const badKey = Math.random().toString();
const anotherBadKey = Date.now().toString();