Embracing Clean Architecture: A Journey to Better Code
Tags: cleancode, architecture, typescript, express
Published: 2023-10-19 08:27:02

"DevReferral's journey from MVC to Clean Architecture: Discover how adopting Clean Architecture improved code quality, enabled Test-Driven Development (TDD), and paved the way for scalability, all while reducing technical debt. Explore the benefits of this transformation for startups seeking resilient and adaptable software solutions."

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>In the fast-paced world of startups, it's crucial to build a strong foundation for your software from the very beginning. One of the most common challenges startups face is maintaining code that can adapt to evolving requirements while remaining maintainable and testable. At DevReferral, we embarked on a journey to transform our codebase by adopting Clean Architecture, and in this article, we'll share our experiences and insights along the way.

## <u>The Road to Clean Architecture</u>

### DevReferral began as a small startup with big ambitions. Like many startups, we initially developed our application using the traditional MVC (Model-View-Controller) architecture with JavaScript in an Express.js Node.js app. This choice allowed us to quickly prototype and develop our application, but it came with its set of challenges.
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### Our MVC architecture led to a tightly coupled system, where dependencies were intertwined, making any change a complex, error-prone process. To exacerbate the issue, our testing strategy primarily focused on router-level tests using tools like Supertest, leaving individual modules of code untested. This practice left us vulnerable to regressions and made the development process slower and riskier.
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### As we realized the limitations of our initial architecture, we began exploring alternative approaches. Domain-Driven Design (DDD) and Clean Architecture stood out as promising options, each offering a unique set of benefits. Ultimately, we decided to adopt Clean Architecture because of its clear separation of concerns and its potential to facilitate the transition to microservices in the future.
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**<u>Understanding Clean Architecture</u>**

### Clean Architecture, introduced by Robert C. Martin, is a software architectural pattern that emphasizes modularity, maintainability, and testability. At its core, Clean Architecture advocates for a strict separation of concerns by dividing the codebase into concentric circles or layers, each with a specific responsibility. Let's explore these layers:
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1. **Entities**: At the center of the architecture are the entities, which represent the core business domain. These entities are independent of any external frameworks or technologies and encapsulate the business rules.
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2. **Use Cases**: Surrounding the entities are use cases or interactors. These use cases define the application's business logic. They serve as an intermediary layer between the entities and the external world.
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3. **Interfaces**: Moving outward, we have the interfaces layer. This layer defines the boundaries through which data flows in and out of the application. It includes interfaces for communication with external systems, such as APIs and databases.
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4. **Frameworks and Drivers**: The outermost layer consists of frameworks and drivers. This layer is responsible for handling external concerns like the user interface, web frameworks (e.g., Express.js), and database access. It's essential to note that this layer depends on the inner layers, but the inner layers remain independent of the outer layers.

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**<u>Benefits of Clean Architecture</u>**
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1. **Separation of Concerns**: Clean Architecture enforces a strict separation of concerns, making it easier to reason about different parts of your application. This separation improves code organization and maintainability.
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2. **Test-Driven Development (TDD)**: Clean Architecture facilitates the practice of TDD by allowing you to write isolated unit tests for each component. With well-defined boundaries, it becomes simpler to mock dependencies and ensure that your code behaves as expected.
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3. **Scalability and Adaptability**: By decoupling the core business logic from external frameworks and technologies, Clean Architecture makes it easier to adapt to changing requirements and even transition to microservices when your startup grows.
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4. **Reduced Technical Debt**: With cleaner code and well-defined boundaries, you'll accumulate less technical debt over time. This leads to a more efficient development process and fewer bugs.
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**<u>Our Journey with Clean Architecture</u>**
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Adopting Clean Architecture at DevReferral was not without its challenges. Here are some key steps we took on our journey:
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1. **Education**: We invested time in understanding the principles of Clean Architecture thoroughly. This involved reading books, articles, and attending workshops to ensure our team had a shared understanding of the approach.
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2. **Refactoring**: We started refactoring our existing codebase incrementally. This process involved identifying the core entities and use cases and gradually migrating them to fit the Clean Architecture structure.
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3. **Dependency Injection**: We adopted dependency injection to manage dependencies between layers. This allowed us to replace real implementations with mocks during testing, making our unit tests more isolated.
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4. **Testing Culture**: We cultivated a testing culture within our team. We began writing unit tests for all our use cases and entities to ensure they behaved correctly. This approach helped us identify and fix issues early in the development process.
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5. **Code Reviews and Knowledge Sharing**: We encouraged code reviews and knowledge sharing sessions among team members. This facilitated learning and ensured that the Clean Architecture principles were consistently applied.
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**<u>Conclusion</u>**
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In the journey of adopting Clean Architecture at DevReferral, we witnessed a significant transformation in our codebase. The separation of concerns, emphasis on testability, and scalability provided by Clean Architecture have empowered our team to build more robust and adaptable software.
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While transitioning to Clean Architecture required effort and commitment, the benefits it brought to our startup far outweighed the initial challenges. Clean Architecture has not only improved our code quality but also set the stage for future growth and the potential transition to microservices.
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As a startup, investing in Clean Architecture early on has proven to be a wise decision. It's a testament to the importance of building a solid foundation for your software, one that can withstand the evolving demands of your business.
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In conclusion, if you're a startup founder or developer looking to build maintainable, scalable, and testable software, consider embarking on your own journey to Clean Architecture. It's a path that can lead to code that's not only clean but also resilient in the face of change, ultimately setting your startup on a path to success.