Setting and deleting entries from WeakMap

We've seen how to use Maps in a variety of situations. There is another new class in ECMAScript that behaves in a very similar way, but has some helpful properties. The WeakMap, like Map, is a key-value data structure.

In this recipe, we'll take a look at how to add and remove elements from a WeakMap with the set and delete methods. And we'll also see how they differ from the Map class.

Getting ready

This recipe assumes that you already have a workspace that allows you to create and run ES modules in your browser. If you don't, refer to 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 11-07-set-and-delete-from-weakmap.
3. Create a main.js file that defines a new class named Rocket that takes a constructor argument name and assigns it to an instance property:

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

4. Create an enum of various launch sites...