A full-stack application where users communicate through numbers and mathematical operations, creating tree-like calculation chains similar to social media comment threads.

This project follows Hexagonal Architecture (Ports & Adapters) pattern:

• Domain Layer: Core business logic, entities, and use cases
• Ports: Interfaces defining contracts (primary for input, secondary for output)
• Adapters: Implementations (HTTP controllers, PostgreSQL repositories)

• Node.js + TypeScript
• Express.js
• PostgreSQL with Prisma ORM
• JWT for authentication
• bcryptjs for password hashing

• React + TypeScript
• Vite
• Axios for API calls

calculation-tree-app/
├── backend/
│   ├── src/
│   │   ├── domain/
│   │   │   ├── entities/          # Domain models
│   │   │   └── use-cases/         # Business logic
│   │   ├── ports/
│   │   │   ├── primary/           # Input interfaces (use cases)
│   │   │   └── secondary/         # Output interfaces (repositories)
│   │   ├── adapters/
│   │   │   ├── primary/           # HTTP controllers, routes
│   │   │   └── secondary/         # Database repositories
│   │   └── index.ts
│   ├── prisma/
│   │   └── schema.prisma
│   └── package.json
├── frontend/
│   ├── src/
│   │   ├── components/            # React components
│   │   ├── contexts/              # React contexts
│   │   ├── services/              # API services
│   │   └── App.tsx
│   └── package.json
└── docker-compose.yml

• Node.js (v18 or higher)
• Docker and Docker Compose (for local database)
• PostgreSQL (if not using Docker)

1. Clone the repository

   git clone <repository-url>
   cd calculation-tree-app

2. Start PostgreSQL database

   docker-compose up -d

3. Backend Setup

   cd backend
   npm install
   
   # Create .env file
   cp .env.example .env
   # Edit .env and set:
   # DATABASE_URL="postgresql://calculation_user:calculation_password@localhost:5432/calculation_tree?schema=public"
   # JWT_SECRET="your-secret-key"
   # PORT=3001
   
   # Generate Prisma client
   npx prisma generate
   
   # Run migrations
   npx prisma migrate dev
   
   # Start backend server
   npm run dev

4. Frontend Setup

   cd frontend
   npm install
   
   # Create .env file (optional, defaults to http://localhost:3001/api)
   # VITE_API_URL=http://localhost:3001/api
   
   # Start frontend dev server
   npm run dev

5. Access the application

   • Frontend: http://localhost:5173
   • Backend API: http://localhost:3001

See DEPLOYMENT.md for the complete deployment guide.

Backend (Railway):

1. Push code to GitHub
2. Create new project on Railway
3. Add PostgreSQL database
4. Set environment variables: DATABASE_URL, JWT_SECRET
5. Deploy backend service
6. Run migrations: npx prisma migrate deploy

Frontend (Vercel):

1. Import project from GitHub (set root directory to frontend)
2. Set environment variable: VITE_API_URL=https://your-backend.railway.app/api
3. Deploy

See DEPLOYMENT.md for detailed instructions and troubleshooting.

• POST /api/auth/register - Register a new user
• POST /api/auth/login - Login user

• GET /api/calculations/starting-numbers - Get all starting numbers (public)
• GET /api/calculations/operations/:parentType/:parentId - Get operations for a parent (public)
• POST /api/calculations/starting-numbers - Create starting number (authenticated)
• POST /api/calculations/operations - Create operation (authenticated)

• ✅ View calculation tree as unregistered user
• ✅ User registration and authentication
• ✅ Create starting numbers (authenticated users)
• ✅ Add operations to starting numbers or other operations
• ✅ Recursive calculation tree display
• ✅ Real-time result calculation

• npm run dev - Start development server with hot reload
• npm run build - Build for production
• npm start - Start production server
• npx prisma studio - Open Prisma Studio to view database

• npm run dev - Start development server
• npm run build - Build for production
• npm run preview - Preview production build

• users: User accounts with username and hashed password
• starting_numbers: Initial numbers that start calculation chains
• operations: Mathematical operations (+,-,*,/) that build on starting numbers or other operations

ISC