Summary
In this chapter, we have introduced JavaScript's type system, understood functions as first-class objects in JavaScript, seen how JavaScript differs from other object-oriented languages, implemented inheritance using prototypes and classes, and learned the new features of ECMAScript 2015 (ES6) that make the language safer and more intuitive to use.
Now that you have a firm grounding in JavaScript, you can start writing Node.js applications with confidence. In the next chapter, we will expand on our Express project and see how the module system in Node.js allows us to structure our codebase.