Nodejs and Express framework

Work with Nginx:

Nginx works as a front end server, which in this case proxies the requests to a node.js server.

https://stackoverflow.com/questions/5009324/node-js-nginx-what-now

Reason why nodejs need to work with another webserver:

https://stackoverflow.com/questions/16770673/using-node-js-only-vs-using-node-js-with-apache-nginx

nginx help to setup privilege, handle static file request, better the security

Routing

module loading system: export, require