Express and the MVC paradigm

Express doesn't enforce an opinion on how you should structure the Model, View, and Controller modules of your application, or whether you should follow any kind of MVC paradigm at all. As we learned in the previous chapter, the blank application created by the Express Generator provides two aspects of the MVC model:

• The views directory contains template files, controlling the display portion, corresponding to the View.
• The routes directory contains code implementing the URLs recognized by the application and coordinating the response to each URL. This corresponds to the controller.

This leaves you wondering where to put code corresponding to the model. Models hold the application data, changing it as instructed by the controller and supplying data requested by View code. At a minimum, the Model code should be in separate modules from the Controller code. This is to ensure a clean separation of concerns, for example, to ease the unit testing of each.

The approach...