So what is a module? Essentially, a module is a separate TypeScript file that exposes classes, interfaces, or functions for reuse in other parts of the project. Creating modules helps to structure your code files into logical groups. As your application becomes larger and larger, it makes sense to have each of your Models, Views, Controllers, helper functions, and so on, in separate source files, so that they can be easily found.

Consider the following directory tree:

In this project structure, we have a separate directory for controllers, models, utils, and views. Within each of these directories, we have several files. Each filename is a clear indication of what we expect the file to contain. A FooterControler.ts file, for example, is expected to contain a controller class that handles the footer of our application. This structure makes our programming lives much...