Using a singleton to manage instances

Sometimes, there are objects that are resource intensive. They may require time, memory, battery power, or network usage that are unavailable or inconvenient. It is often useful to manage the creation and sharing of instances.

In this recipe, we'll see how to use singletons to manage instances.

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 09-05-singleton-to-manage-instances.
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. Add a constructor takes a name constructor argument and assigns it to an instance property:

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

5. Create a RocketManager object that has a rockets...