I am reading a book (Getting MEAN by Simon Holmes) about MEAN Stack which talks about different architectures that can be used while developing an app in MEAN Stack and I got a little confused with that.First I'll tell you how I develop applications in MEAN:My Front-End is a templating engine like EJS or Jade.I render pages through my Node/Express.js Server.I also use AngularJS on the front-end, I have angularJS controllers to manage the scope and functionalities of different features in the app and I use Angular Services to communicate with my Node.js Server and make HTTP calls to my routes.I create a Node.js Server using Express.JS and then create a REST API.I create API routes using Express.jsI use MongoDB for database and mongoose for database connections etcThe above described architecture is the one I use but the book I am reading talked about a few more and I am confused about how they are setup and work.The 3 different architectures described in the book are:A Node.js and Express ApplicationA Node.js and Express Application with AngularJS additions for interactivityAn AngularJS SPA (Single Page Application)Heres the image representation of the 3 architecture in the book:Can anyone explain how these 3 approaches are different from what I do and how they are setup? 
Different type of MEAN Stack Architectures
architecture;javascript;api;node.js;angularjs