In this post we’ll go through all the essential steps that will eventually lead you to the construction of a new self-contained web application based on a RESTful API built with the Scala Play framework and consumed by an Angular 7 front end. We will build the API from scratch putting the front end code in the same repository (within the /ui folder).

In this post we’re going to see what is a Category and in particular a Monoid, and to dive into this subject we’ll take advantage of the Scala programming language. So let’s start from the beginning and let’s try to keep the things simple and clear, because as we’ll see in a moment, the Monoid is a very simple structure defined only by its algebra.

Start programming and experimenting with a functional programming language like Scala might not seem simple at first sight. So, to get your feet wet it’s useful to have the very essential in a single place. I started writing this post in the form of a gist, but then I realized that maybe it was better to share it with the community.

S.O.L.I.D. principles