Express doesn't enforce an opinion on how you should structure the Model, View and Controller modules of your application. As we learned in the previous chapter, the blank application created by the Express Generator provides two aspects of the MVC model:
viewsdirectory contains template files, controlling the display portion, corresponding to the View.
routesdirectory contains code implementing the URLs recognized by the application and coordinating the response to each URL. This corresponds to the Controller.
This leaves one wondering where to put code corresponding to the Model. The role of the Model is to hold application data, changing it as instructed by the Controller, and supplying data requested by ...