Node.js Design Patterns: DDD and clean architectures in Node

[Albareto McKenzie]

Hi there,

One thing I always struggle with when I am coding node solutions is how to make a clean architecture separating things like domains, infrastructure, etc... I struggle on injecting dependencies (specially on the domain layer) and at the end I just end up importing them directly from other folder. I am thinking on dependencies such as the logger, event managers, etc...
I come from Java world where I find it much more intuitive and have serious problems when trying to replicate it in Node.

Thanks!

[Mario Casciaro]

Hi Albareto,

in my opinion, one of the features that make Node.js enjoyable to use is that dependencies are explicit. In Java is very common to use a dependency injection container, which adds a level of indirection, which somewhat complicates the readability of the code. In Node.js, if you want to import a singleton, you can just export an instance from a module (e.g. module.export = new MyClass()) and import the singleton with a simple call to require() or import. It's that simple.
To me, a "clean" architecture in Node.js, means creating modules that do only one thing and well (cohesion) and that expose a minimal interface (information hiding). Organizing those modules in a coherent directory structure is also important.

To be honest, in my early days of Node.js, I too struggled to apply the knowledge I had acquired from using Java and other strongly typed languages. In fact, one of my early Node.js projects was a dependency injection container. With time I learned to let go of my old mindset and accepted the fact that in Node.js certain things are just basic simple and in my opinion, that's  amazing.

PS: This is such a common question that in the book we have dedicated section called "Wiring modules" where we talk exactly about that.

[Albareto McKenzie]

Mario Casciaro wrote:Hi Albareto,

in my opinion, one of the features that make Node.js enjoyable to use is that dependencies are explicit. In Java is very common to use a dependency injection container, which adds a level of indirection, which somewhat complicates the readability of the code. In Node.js, if you want to import a singleton, you can just export an instance from a module (e.g. module.export = new MyClass()) and import the singleton with a simple call to require() or import. It's that simple.
To me, a "clean" architecture in Node.js, means creating modules that do only one thing and well (cohesion) and that expose a minimal interface (information hiding). Organizing those modules in a coherent directory structure is also important.

To be honest, in my early days of Node.js, I too struggled to apply the knowledge I had acquired from using Java and other strongly typed languages. In fact, one of my early Node.js projects was a dependency injection container. With time I learned to let go of my old mindset and accepted the fact that in Node.js certain things are just basic simple and in my opinion, that's  amazing.

PS: This is such a common question that in the book we have dedicated section called "Wiring modules" where we talk exactly about that.

Yes, I think the key is to let it go from other programming paradigms. I think (this is a personal self-assessment) that we tend also to overengineer solutions lots of times.

Thanks a lot Mario
BTW I have won a copy and I will read it very carefully when I receive it. Thanks again.