These modern frameworks provide developers an easy path to organizing their code using variations of a pattern known as MVC (Model-View-Controller). MVC separates the concerns in an application down into three parts

JavaScript ‘MVC’ frameworks that can help us structure our code don’t always strictly follow the above pattern. Some frameworks will include the responsibility of the Controller in the View (e.g Backbone.js) whilst others add their own opinionated components into the mix as they feel this is more effective.

For this reason we refer to such frameworks as following the MV* pattern, that is, you’re likely to have a View and a Model, but more likely to have something else also included.