Classes and objects

As a quick refresher, objects are a collection of properties and methods. We saw them in Chapter 3, JavaScript Multiple Values. The properties of an object should have sensible names. So for example, if we have a person object, this object could have properties called age and lastName that contain values. Here is an example of an object:

let dog = { dogName: "JavaScript", 
            weight: 2.4, 
            color: "brown", 
            breed: "chihuahua"
          };

Classes in JavaScript encapsulate data and functions that are part of that class. If you create a class, you can later create objects using that class using the following syntax:

class ClassName {
  constructor(prop1, prop2) {
    this.prop1 = prop1;
    this.prop2 = prop2;
  }
}
 
let obj = new ClassName("arg1", "arg2");

This code defines a class with ClassName as a name, declares an obj variable, and initializes this with a new...