scrabill/fewpjs-oo-initializing-instances-online-web-pt-061019

Initializing Instances

Learning Goals

• Create a class in JavaScript using the class keyword
• Provide a JavaScript class's constructor instantiation data for an instance

Introduction

In this lab, we are going to practice creating Object Oriented classes and instances using JavaScript's class keyword. We are also going to use JavaScript's class constructor to instantiate data into a class. In other words, we're going to create a class, and then put some data in it.

Create a class in JavaScript using the class keyword

Remember, when we want to create a class in JavaScript, we want to create it using the class keyword:

class Dog {}

Provide a JavaScript class's constructor instantiation data for an instance

Within our class, JavaScript class's constructor allows us to pass data to our new class.

class Dog {
  constructor(name, breed) {
    this.name = name;
    this.breed = breed;
  }
}

You could then create data for the class above by doing something like the following:

let bigFluffyDog1 = new Dog("Buzz", "greatPyrenees");
let bigFluffyDog2 = new Dog("Woody", "labrador");

bigFluffyDog1; // => Dog { name: 'Buzz', breed: 'greatPyrenees' }
bigFluffyDog2; // => Dog { name: 'Blue', breed: 'labrador' }

Instructions

To practice OOP concepts, let's create 3 classes that use constructor methods. These constructors will assign properties based on initial parameters.

1. Create a class for Breakfast. Breakfast will have a constructor with a food and a drink.
2. Create a class for Lunch. Lunch will have a constructor with a salad, a soup, and a drink.
3. Create a class for Dinner. Since dinner is a little bit fancier, Dinner will have a constructor with salad, soup, entree, and dessert. Indicate that dessert is intended to be a private property by including an underscore (_) at the beginning.

Conclusion

By effectively creating classes and instances, you have mastered the beginning of Object Oriented JavaScript. Feel free to play around with your newly created classes to create more instances!

Resources

• Classes