Scalable React Application Architecture Guide

🧩 1. Project Structure & Organizing Code

• Feature-based directory layout:

src/
├── features/         # Feature-specific logic
├── components/       # Reusable presentational components
├── hooks/            # Custom hooks
├── services/         # API clients and side-effects
├── store/            # Global state (Redux/Zustand/Recoil)
├── utils/            # Pure utility functions
└── App.tsx / index.tsx

`

• Barrel exports: Use index.ts files inside folders to group and simplify imports.

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🛠 2. Design Patterns & Component Architecture

• Container vs Presentational Components:
• Container: Handles state, API calls.

• Presentational: Stateless UI component, receives props.

• Hooks & Custom Hooks:

• Shared logic should go into custom hooks like useAuth, useForm, useFetch.

• Higher-Order Components (HOC):

• For reusable behaviors (e.g., logging, auth gating).

• Compound Components & Context:

• Enable scoped, flexible UIs using parent-child coordination.

• Memoization:

• Use React.memo, useMemo, useCallback for performance.

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🎯 3. State & Data Management

• Global state management:
• Use Redux Toolkit, Recoil, Zustand, or Context API.

• Minimize global state. Keep UI-specific state local.

• Unidirectional data flow:

• Actions → Reducers → State → Props → UI

• Side-effect management:

• Use Redux Thunk, Redux Saga, React Query, or SWR for async ops.

---

📡 4. API Layer & Services

• Service abstraction:
• Encapsulate all API calls in /services using Axios/Fetch.

• Example:
  ts
export const getUserProfile = () => api.get('/user/profile');


• Error & loading handling:

• Use React Query or loading/error state wrappers.

• Authentication tokens:

• Prefer HttpOnly cookies for secure auth.

• Abstract auth/session logic in dedicated services or hooks.

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🧪 5. Code Quality & Testing

• Linting:

• Use ESLint, Prettier, and Husky for commit-time lint checks.

• Testing:

• Unit tests: Vitest/Jest + React Testing Library

• Integration/E2E: Playwright or Cypress

• Testing strategy:

• Write tests for:

  • Pure functions (utils, services)
  • Component rendering + behavior
  • Hooks logic
  • API handling

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🚀 6. Performance Optimization

• Code splitting:

• Lazy load route-based components using React.lazy() and Suspense.

• Memoization:

• Prevent re-renders with React.memo, useMemo, and useCallback.

• Bundle analysis:

• Use tools like webpack-bundle-analyzer or Vite plugins.

• Avoid over-rendering:

• Lift state only when necessary.

• Split complex components.

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🔐 7. Security & Error Handling

• Error boundaries:

• Use ErrorBoundary components to catch rendering issues.

• Global error handling:

• Wrap API services to catch and standardize error handling.

• Security practices:

• Validate all inputs.

• Avoid XSS via sanitization.

• Use secure cookies and SameSite attributes.

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🛡️ 8. Bulletproof React Template (by alan2207)

Repo: github.com/alan2207/bulletproof-react

• Feature-first folder structure
• Modular state management (Redux Toolkit or Zustand)
• Centralized API abstraction
• Forms (React Hook Form + Zod)
• Routes split per feature
• Testing setup with Vitest, Testing Library, Playwright
• Styling with Tailwind/Shadcn UI
• Environment validation (Zod)
• Vite-based build pipeline

---

🧭 Sample Folder Structure

`

src/
├── features/
│   └── auth/
│       ├── components/
│       ├── hooks/
│       ├── api/
│       └── AuthPage.tsx
├── components/
├── services/
├── hooks/
├── store/
├── routes/
├── utils/
├── App.tsx
└── main.tsx

---

✅ Final Checklist for Scalable React Apps

• [x] Feature-based directory structure
• [x] Clear separation of concerns (logic vs UI)
• [x] Abstracted services and state
• [x] Custom hooks for shared logic
• [x] Error boundaries and global error handling
• [x] API and state decoupling
• [x] Secure token storage practices
• [x] CI-ready with linting, formatting, and testing

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📚 References

• React Architecture Patterns – Bacancy
• Bulletproof React – GitHub
• Scalable React App Design – Dev.to