Lesson 3: Two Dogs - Your First Class

Two Dogs Build two objects from one blueprint.

1class Dog {

2 constructor(name) {

3 this.name = name;

4 }

7const rex = new Dog("Rex");

8const bella = new Dog("Bella");

9console.log(rex.name);

10console.log(bella.name);

Terminal

$ node main.js

Rex

Bella

Every line, explained

class Dog {: class Dog { ... } defines a class: a blueprint describing what every Dog has and can do. A blueprint on its own does nothing; it is a plan, waiting to be built from.
constructor(name) {: constructor is a special method that runs AUTOMATICALLY when new Dog(...) is built. It is where you fill in the object's starting values. (Note there is no function keyword on methods inside a class.)
this.name = name;: Each new dog gets its OWN name box.
}: This } closes the constructor.
}: This } closes the class.
const rex = new Dog("Rex");: One blueprint...
const bella = new Dog("Bella");: ...as many objects as you like. Think of one house plan and a whole street of houses. bella's name box is completely separate from rex's.
console.log(rex.name);: console.log(...) works exactly as in Intro to JavaScript.
console.log(bella.name);: console.log(...) works exactly as in Intro to JavaScript. Two objects, two different names.