Clean Architecture with NestJS

article: https://medium.com/@peterkracik

This project demonstrates the implementation of Clean Architecture principles using the NestJS framework. It serves as a guide for structuring a NestJS application to ensure separation of concerns, maintainability, and scalability.

Project Structure

The project is organized into several layers, each with a specific responsibility:

• Domain Layer: Contains the core business logic and domain entities. This layer is independent of frameworks and external libraries.

• Use Cases Layer: Implements application-specific business rules. Each use case is represented as a service with a single responsibility.

• Interface Adapters Layer: Acts as a bridge between the framework and the domain layer. This includes controllers, presenters, and gateways.

• Frameworks and Drivers Layer: Contains the NestJS framework and any third-party libraries. This layer handles interactions with external systems, such as databases and APIs.

Key Features

• Dependency Injection: Utilizes NestJS's powerful dependency injection system to manage service instances and promote loose coupling between components.

• Repository Pattern: Abstracts data access logic, allowing easy swapping of data sources without affecting the business logic.

• Modular Design: Encourages the separation of concerns by organizing the application into distinct modules.

• Interchangeable Components: Demonstrates how to swap out components like databases or notification services with minimal impact on the application.

Getting Started

Prerequisites

• Node.js
• Yarn

Installation

yarn install

Environment variables

copy .env.template to .env

Running the Application

1. Start docker to provide a database, you can start the docker via

docker compose up

2. Start the development server:

yarn start:dev

3. Access the application at http://localhost:3000.

Testing

Run the tests using:

yarn test
yarn test:e2e

Customization

• Environment Configuration: Use environment variables to configure different settings for development, testing, and production environments.
• Extending Functionality: Add new use cases or integrate additional services by following the established architectural patterns.

Contributing

Contributions are welcome! Please submit a pull request or open an issue to discuss your ideas.

License

This project is licensed under the MIT License. See the LICENSE file for details.

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