Currency Exchange Application

🚀 Description

This project is a sophisticated currency exchange platform that offers:

• API for Currency Exchange: Calculate and perform currency exchanges with ease.
• Real-time Updates: Stay updated with the latest currency reserves through WebSockets.
• Interactive Front-end: A sleek React-based interface for an enhanced user experience.

The application leverages Domain-Driven Design (DDD) principles and supports both in-memory and PostgreSQL databases. For testing convenience, the default mode is in-memory, but you can easily switch the repository implementation, seesrc/app.module.

🛠️ Installation

Get started with the following commands:

$ npm install

🚀 Running the Application

Choose your preferred mode to run the application:

Development Mode

$ npm run start

Watch Mode

$ npm run start:dev

Production Mode

$ npm run start:prod

Once the application is running, you can access the frontend at http://localhost:3000

📚 API Documentation

The API documentation is available through Swagger UI. Once the application is running, you can access the API documentation at:

http://localhost:3000/api

This interactive documentation provides detailed information about all available endpoints, request/response schemas, and allows you to test the API directly from the browser.

🧪 Testing

Ensure the robustness of the application with these commands:

Unit Tests

$ npm run test

End-to-End Tests

$ npm run test:e2e

🌟 Features

• Currency Exchange API: Endpoints for calculating and performing currency exchanges.
• Real-time Updates: WebSocket integration for live updates of currency reserves.
• Front-end Interface: A React-based interface for user interactions.
• Currency Precision:
  • TWD (New Taiwan Dollar) is handled in whole number units (no decimal places).
  • USD (US Dollar) is handled with precision up to 2 decimal places.

🛠️ Technologies Used

• Backend: NestJS, TypeScript, MikroORM, PostgreSQL, EventEmitter, DDD
• Frontend: React, Axios, Socket.IO
• Testing: Jest

📁 Project Structure

currency-exchange/
├── src/
│   ├── application/
│   ├── domain/
│   │   ├── core/
│   │   ├── exchange/
│   │   └── reserve/
│   ├── infrastructure/
│   │   └── persistence/
│   │       ├── memory/
│   │       └── mikro-orm/
│   └── interfaces/
│       ├── http/
│       │   └── client/
│       └── websocket/
├── test/
└── README.md

• src/: Contains the main application code
  • application/: Application services and DTOs
  • domain/: Core domain logic and entities
  • infrastructure/: Implementation details (e.g., database)
  • interfaces/: API controllers and client-side code
• test/: Contains test files