If you go back to Chapter 1, Object-Oriented JavaScript, and review the Object-oriented programming section, you'll see that you already know how to apply most of them to JavaScript. You know what objects, methods, and properties are. You know that there are no classes in ES5, although you can achieve them using constructor functions. ES6 introduces the notion of classes; we will take a detailed look at how ES6 classes work in the next chapter. Encapsulation? Yes, the objects encapsulate both the data and the means (methods) to do something with the data. Aggregation? Sure, an object can contain other objects. In fact, this is almost always the case since methods are functions and functions are also objects.
Now, let's focus on the inheritance part. This is one of the most interesting features, as it allows you to reuse existing code, thus promoting laziness, which is likely to be what brought human species to computer programming in the first place.
JavaScript is a...