Project Setup & Architecture

Guide for setting up React Native/Expo project infrastructure.

When to Use

• Initializing TypeScript configuration
• Setting up database layer
• Configuring state management
• Installing and configuring testing
• Creating directory structure
• Adding linting and formatting

Setup Workflows

TypeScript Setup

# Install TypeScript
npm install --save-dev typescript @types/react @types/react-native

# Create tsconfig.json
npx tsc --init

{
  "extends": "expo/tsconfig.base",
  "compilerOptions": {
    "strict": true,
    "skipLibCheck": true,
    "jsx": "react-native"
  }
}

Directory Structure

# Create feature-sliced architecture
mkdir -p src/{app,features,shared,db,theme}
mkdir -p src/shared/{components,hooks,utils,types}

Database Setup (SQLite + Drizzle)

# Install dependencies
npx expo install expo-sqlite
npm install drizzle-orm
npm install --save-dev drizzle-kit

# Create structure
mkdir -p src/db/{schema,migrations}

// src/db/client.ts
import * as SQLite from 'expo-sqlite';
import { drizzle } from 'drizzle-orm/expo-sqlite';

const db = SQLite.openDatabaseSync('app.db');
export const drizzle = drizzle(db);

State Management (Zustand)

npm install zustand

// src/shared/stores/useAppStore.ts
import { create } from 'zustand';

interface AppState {
  count: number;
  increment: () => void;
}

export const useAppStore = create<AppState>((set) => ({
  count: 0,
  increment: () => set((state) => ({ count: state.count + 1 })),
}));

Testing Setup

npm install --save-dev jest @testing-library/react-native

// package.json
{
  "scripts": {
    "test": "jest"
  }
}

Linting & Formatting

npm install --save-dev eslint prettier
npx eslint --init

Configuration Files

app.json (Expo Configuration)

{
  "expo": {
    "name": "MyApp",
    "slug": "my-app",
    "version": "1.0.0",
    "platforms": ["ios", "android"],
    "ios": {
      "bundleIdentifier": "com.company.myapp"
    },
    "android": {
      "package": "com.company.myapp"
    }
  }
}

package.json Scripts

{
  "scripts": {
    "start": "expo start",
    "android": "expo start --android",
    "ios": "expo start --ios",
    "test": "jest",
    "lint": "eslint src/",
    "type-check": "tsc --noEmit"
  }
}

Best Practices

1. Incremental Setup: Install and configure one system at a time
2. Verify Installation: Test each setup before moving to next
3. Check Dependencies: Ensure compatibility with Expo SDK
4. Use Expo Install: For Expo packages, use npx expo install
5. Version Control: Commit after each successful setup step

Common Tasks

Add New Dependency

# Check if it's an Expo SDK package
npx expo install package-name

# Otherwise use npm
npm install package-name

Create New Feature Module

mkdir -p src/features/my-feature/{components,hooks,services,types}
touch src/features/my-feature/index.ts

Generate Database Migration

npx drizzle-kit generate:sqlite
npx drizzle-kit push:sqlite

Verification Checklist

After setup, verify:

• TypeScript compiles without errors (npx tsc --noEmit)
• App runs on both iOS and Android
• Tests run successfully (npm test)
• Linting passes (npm run lint)
• Database connects and queries work
• State management functions correctly

Resources

• Expo Configuration
• TypeScript with Expo