File Organization

Project File Organization

When to use this skill

• New Projects: Initial folder structure design
• Project Growth: Refactoring when complexity increases
• Team Standardization: Establish consistent structure

Instructions

Step 1: React/Next.js Project Structure

src/
├── app/                      # Next.js 13+ App Router
│   ├── (auth)/               # Route groups
│   │   ├── login/
│   │   └── signup/
│   ├── (dashboard)/
│   │   ├── layout.tsx
│   │   ├── page.tsx
│   │   └── settings/
│   ├── api/                  # API routes
│   │   ├── auth/
│   │   └── users/
│   └── layout.tsx
│
├── components/               # UI Components
│   ├── ui/                   # Reusable UI (Button, Input)
│   │   ├── Button/
│   │   │   ├── Button.tsx
│   │   │   ├── Button.test.tsx
│   │   │   └── index.ts
│   │   └── Input/
│   ├── layout/               # Layout components (Header, Footer)
│   ├── features/             # Feature-specific components
│   │   ├── auth/
│   │   └── dashboard/
│   └── shared/               # Shared across features
│
├── lib/                      # Utilities & helpers
│   ├── utils.ts
│   ├── hooks/
│   │   ├── useAuth.ts
│   │   └── useLocalStorage.ts
│   └── api/
│       └── client.ts
│
├── store/                    # State management
│   ├── slices/
│   │   ├── authSlice.ts
│   │   └── userSlice.ts
│   └── index.ts
│
├── types/                    # TypeScript types
│   ├── api.ts
│   ├── models.ts
│   └── index.ts
│
├── config/                   # Configuration
│   ├── env.ts
│   └── constants.ts
│
└── styles/                   # Global styles
    ├── globals.css
    └── theme.ts

Step 2: Node.js/Express Backend Structure

src/
├── api/                      # API layer
│   ├── routes/
│   │   ├── auth.routes.ts
│   │   ├── user.routes.ts
│   │   └── index.ts
│   ├── controllers/
│   │   ├── auth.controller.ts
│   │   └── user.controller.ts
│   └── middlewares/
│       ├── auth.middleware.ts
│       ├── errorHandler.ts
│       └── validation.ts
│
├── services/                 # Business logic
│   ├── auth.service.ts
│   ├── user.service.ts
│   └── email.service.ts
│
├── repositories/             # Data access layer
│   ├── user.repository.ts
│   └── session.repository.ts
│
├── models/                   # Database models
│   ├── User.ts
│   └── Session.ts
│
├── database/                 # Database setup
│   ├── connection.ts
│   ├── migrations/
│   └── seeds/
│
├── utils/                    # Utilities
│   ├── logger.ts
│   ├── crypto.ts
│   └── validators.ts
│
├── config/                   # Configuration
│   ├── index.ts
│   ├── database.ts
│   └── env.ts
│
├── types/                    # TypeScript types
│   ├── express.d.ts
│   └── models.ts
│
├── __tests__/                # Tests
│   ├── unit/
│   ├── integration/
│   └── e2e/
│
└── index.ts                  # Entry point

Step 3: Feature-Based Structure (Large-Scale Apps)

src/
├── features/
│   ├── auth/
│   │   ├── components/
│   │   │   ├── LoginForm.tsx
│   │   │   └── SignupForm.tsx
│   │   ├── hooks/
│   │   │   └── useAuth.ts
│   │   ├── api/
│   │   │   └── authApi.ts
│   │   ├── store/
│   │   │   └── authSlice.ts
│   │   ├── types/
│   │   │   └── auth.types.ts
│   │   └── index.ts
│   │
│   ├── products/
│   │   ├── components/
│   │   ├── hooks/
│   │   ├── api/
│   │   └── types/
│   │
│   └── orders/
│
├── shared/                   # Shared across features
│   ├── components/
│   ├── hooks/
│   ├── utils/
│   └── types/
│
└── core/                     # App-wide
    ├── store/
    ├── router/
    └── config/

Step 4: Naming Conventions

File Names:

Components:       PascalCase.tsx
Hooks:            camelCase.ts        (useAuth.ts)
Utils:            camelCase.ts        (formatDate.ts)
Constants:        UPPER_SNAKE_CASE.ts (API_ENDPOINTS.ts)
Types:            camelCase.types.ts  (user.types.ts)
Tests:            *.test.ts, *.spec.ts

Folder Names:

kebab-case:       user-profile/
camelCase:        userProfile/       (optional: hooks/, utils/)
PascalCase:       UserProfile/       (optional: components/)

✅ Consistency is key (entire team uses the same rules)

Variable/Function Names:

// Components: PascalCase
const UserProfile = () => {};

// Functions: camelCase
function getUserById() {}

// Constants: UPPER_SNAKE_CASE
const API_BASE_URL = 'https://api.example.com';

// Private: _prefix (optional)
class User {
  private _id: string;

  private _hashPassword() {}
}

// Booleans: is/has/can prefix
const isAuthenticated = true;
const hasPermission = false;
const canEdit = true;

Step 5: index.ts Barrel Files

components/ui/index.ts:

// ✅ Good example: Re-export named exports
export { Button } from './Button/Button';
export { Input } from './Input/Input';
export { Modal } from './Modal/Modal';

// Usage:
import { Button, Input } from '@/components/ui';

❌ Bad example:

// Re-export everything (impairs tree-shaking)
export * from './Button';
export * from './Input';

Output format

Project Template

my-app/
├── .github/
│   └── workflows/
├── public/
├── src/
│   ├── app/
│   ├── components/
│   ├── lib/
│   ├── types/
│   └── config/
├── tests/
├── docs/
├── scripts/
├── .env.example
├── .gitignore
├── .eslintrc.json
├── .prettierrc
├── tsconfig.json
├── package.json
└── README.md

Constraints

Required Rules (MUST)

1. Consistency: Entire team uses the same rules
2. Clear Folder Names: Roles must be explicit
3. Max Depth: Recommend 5 levels or fewer

Prohibited (MUST NOT)

1. Excessive Nesting: Avoid 7+ levels of folder depth
2. Vague Names: Avoid utils2/, helpers/, misc/
3. Circular Dependencies: Prohibit A → B → A references

Best practices

1. Colocation: Keep related files close (component + styles + tests)
2. Feature-Based: Modularize by feature
3. Path Aliases: Simplify imports with @/

tsconfig.json:

{
  "compilerOptions": {
    "baseUrl": ".",
    "paths": {
      "@/*": ["./src/*"],
      "@/components/*": ["./src/components/*"],
      "@/lib/*": ["./src/lib/*"]
    }
  }
}

Usage:

// ❌ Bad example
import { Button } from '../../../components/ui/Button';

// ✅ Good example
import { Button } from '@/components/ui';

References

• React File Structure
• Node.js Best Practices
• Clean Architecture

Metadata

Version

• Current Version: 1.0.0
• Last Updated: 2025-01-01
• Compatible Platforms: Claude, ChatGPT, Gemini

Tags

#file-organization #project-structure #folder-structure #naming-conventions #utilities

Examples

Example 1: Basic usage

Example 2: Advanced usage