如果设计为在客户端上运行，我如何在NodeJS应用程序的服务器端使用javascript库？

I'm diving into NodeJS and Express (it's sooo complicated to me) to build a real-time web app. At the moment, I'm trying to understand how I can use an existing javascript library on the server side. The problem is the library appears to be designed to run on the client side and, as a result, the instructions only show you how to use it on the client side. The library I'm talking about can be found here...I'm diving into NodeJS and Express (it's sooo c