Factory
We'll begin our journey from one of the most common design patterns in Node.js: Factory. As you will see, the Factory pattern is very versatile and has more than just one purpose. Its main advantage is its ability to decouple the creation of an object from one particular implementation. This allows us, for example, to create an object whose class is determined at runtime. Factory also allows us to expose "a surface area" that is much smaller than that of a class; a class can be extended or manipulated, while a factory, being just a function, offers fewer options to the user, making it more robust and easier to understand. Finally, a factory can also be used to enforce encapsulation by leveraging closures.
Decoupling object creation and implementation
We already stressed the fact that, in JavaScript, the functional paradigm is often preferred to a purely object-oriented design for its simplicity, usability, and small surface area. This...