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Exercise: JS Object-Oriented Programming

Objective#

Your objective is to practice OOP concepts and JS class notation syntax.

Steps#

Getting Started#

Exercise Repo: JS Object Oriented Programming

  1. Open your command line and navigate to your repos directory (if you do not have a repos folder, then you can use mkdir repos to create one)
  2. Use this template repository to start a new project in your repos folder: git clone <repo_name>
  3. cd repo_name to navigate into your new repo directory
  4. Start Visual Studio Code and select 'Open Folder'. Then select repo_name to open the folder in the editor (or just type code . in your terminal inside the repo directory)
  5. Follow the instructions on the README.md file to complete exercises
  6. Open the app.js file to get started

Exercise 1#

  • Expanding from our exercise example during the lesson, create a parent class class Person {} with properties for name, pets, residence, and hobbies. The Person class will also have a method info() and soundOff().
  1. Use class notation to create a class named Person
  2. Declare the constructor() method with parameters name (string), pets (number), residence (string), and hobbies (array) allowed to be passed in
  3. The constructor() method assigns this. properties to each parameter
  4. Declare an addHobby() method on the class that takes in a new hobby (string), and adds it to the object's hobbies array property
  5. Declare a removeHobby() method on the class that takes in a hobby (string), and removes the hobby from the object's hobbies array property
  6. Declare a greeting() method that console.log's a generic greeting for a Person... ex: greeting() {console.log("Hello fellow person!")}

Exercise 2#

Now we'll create a subclass Coder that inherits from our Person class

  1. Use class notation to create a class named Coder that inherits from the Person class
  2. Declare the constructor() method with parameters name (string), pets (number), residence (string), and hobbies (array) allowed to be passed in
  3. Call the super() method inside the constructor method and pass in the given parameters
  4. Still inside the constructor body, assign this.occupation as "Full Stack Web Developer"
  5. Override the greeting() method to console.log a custom greeting from a coder...

Exercise 3#

Let's create instances of our classes

  1. Create a variable and assign a Person object to it using the new keyword followed by the class constructor
  2. Create a variable and assign a Coder object to it using the new keyword followed by the class constructor
  3. Call the object methods and console.log the object properties to test your work

Exercise 4#

In this final exercise, we'll create a class that has the functionality of a basic calculator.

  1. Create a class called Calculator
  2. Initialize a result property within the calculator constructor with an initial value of 0
  3. Declare methods on the class that represent basic arithmetic: add(), subtract(), multiply(), divide()
  • These methods should currently take in 2 parameters, and assign the result of the appropriate arithmetic based on the method name to the object's result property
  • Should return the result
  • EXTRA: if only one value is passed in, use the object's current result value as the first value in the operation
  1. Declare a method called displayResult() that will console.log the result property stored on the object
  2. Test your work by instantiating an object from your class (using the class constructor), and calling some of the calculator methods