Patterns for wiring modules

Now that we have discussed some basic theory around dependencies and coupling, we are ready to dive into some more practical concepts. In this section, in fact, we are going to present the main module wiring patterns. Our focus will be mainly pointed towards the wiring of stateful instances, which are, without any doubts, the most important type of dependencies in an application.

Hardcoded dependency

We start our analysis by looking at the most conventional relationship between two modules, which is the hardcoded dependency. In Node.js, this is obtained when a client module explicitly loads another module using require(). As we will see in this section, this way of establishing module dependencies is simple and effective, but we have to pay additional attention to hardcoding dependencies with stateful instances, as this would limit the reusability of our modules.

Building an authentication server using hardcoded dependencies

Let's start our analysis by looking at...