Virtual Pet Game

We’re going to finish this chapter by creating a virtual pet game, based on the classic Tamagotchi toys. This game will involve the player looking after a pet unicorn. The player gets to name their pet unicorn and then needs to decide when to feed it, play with it, and put it to bed.

The game will use a Unicorn class to instantiate an object that represents a pet unicorn. The object will have properties that keep track of how the unicorn is feeling, and methods that allow the player to interact with their pet unicorn. This game will run entirely in the console by entering the methods manually.

Defining the properties

The Unicorn class will need the following properties:

• name: For referring to the unicorn.

• food: For keeping track of how much food the unicorn has in its belly.

• fun: For recording how much fun the unicorn is having.

• energy: For keeping track of how much energy the unicorn has.

Defining the methods

The Unicorn class will also need the following methods:

• eat: This will increase the value of food, because eating will put food in the unicorn’s belly, but it will decrease the value of fun, because standing around eating can be a bit dull.

• sleep: This will increase the value of energy, because sleeping provides the unicorn with some rest, but the value of food will decrease as the food is digested. It will also decrease the value of fun, because sleeping can be a bit boring.

• play: This will increase the value of fun, because playing is fun, but it will decrease the value of energy, because playing can be hard work!

Components of the class

Let’s create the constructor function that will be used to instantiate a new instance of the Unicorn class. It should define the properties outlined above. Let’s add the following class definition to the index.js file: