In the exercise files of this chapter, you will find two directories: Final and Initial. Final contains the final source code of the project, whereas Initial contains the empty source code files and libraries to get started with building the application quickly.

In the Initial directory, you will find a public directory and two files named app.js and package.json. package.json contains the backend dependencies of our app, and app.js is where you will place the backend source code.

The public directory contains files related to the frontend. Inside public/css, you will find bootstrap.min.css, which is the Bootstrap library; inside public/html, you will find index.html, where you will place the HTML code of our app; and in the public/js directory, you will find JS files for jQuery, sha1, and socket.io. Inside public/js, you will also find a main.js file, where you will place the frontend JS code of our app.