I started my journey to try to learn MEAN stack. But then I realized I wanted to use Firebase instead of Mongo.db and Angular2 instead of Angular. I came up to a problem where I had trouble setting up Angular2 with express so that everything was simple and would work fine. trying to find a standard answer for a good setup for Firebase,Express,Angular2, and Node, I saw some posts showing that Express is not anymore necessary when using Firebase. I am still new to these frameworks so I am not sure if I understood it all correctly. I found this post, which kinda answers my question, but it's from 2014 and I know there are new versions of Firebase and express.
What is the difference in Express and Firebase currently? and In what cases should I consider using them both?
Thanks!