Reusable services leveraging OOP concepts

As mentioned, we have only worked with interfaces to represent data. We still want to continue using interfaces when passing data around various components and services. Interfaces are great for describing the kind of properties or functions an implementation has, but they suggest nothing about the behavior of these properties or functions.

With ES2015 (ES6), JavaScript gained native support for classes, which is a crucial concept of the OOP paradigm. Classes are actual implementations of behavior. As opposed to just having a collection of functions in a file, a class can properly encapsulate behavior. A class can then be instantiated as an object using the new keyword.

TypeScript takes the ES2015 (and beyond) implementation of classes and introduces necessary concepts like abstract classes, private, protected, and public properties, and interfaces to make it possible to implement OOP patterns.

OOP is an imperative programming...