Using throw to simulate abstract classes

So far, we've seen how to create and combine classes into a variety of different shapes. Sometimes, however, we want to be able to prevent the creation of a class and only allow instances of extending classes. Other languages provide a facility known as abstract classes. In this recipe, we'll see how to simulate this by throwing errors.

Getting ready

This recipe assumes you already have a workspace that allows you to create and run ES modules in your browser. If you don't, please see the first two chapters.

How to do it...

1. Open your command line application and navigate to your workspace.
2. Create a new folder named 08-10-use-throw-to-simulate-abstract-class.
3. Copy or create an index.html that loads and runs a main function from main.js.

4. Create a main.js file that defines a new class named Rocket. In the constructor, check the constructor of the instance, if it's Rocket, then throw an error:

// main.js 
class Rocket { 
  constructor (name) { 
    this.name ...