The Journey of #100DaysOfCode (@henna_dev)

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#Day68 of 100daysofcode

Today was Good Friday, and as per the name, it did turn out good as well… It was a sunny day, we went for long walks, and dined out :smiling_face_with_three_hearts:

It was a productive day as well… I was stressed out in the past 2-3 days, but today felt better. I continued with the Classes concept in Javascript and learned about inheritance and static methods. I also created a sample Library Catalog project which now I am thinking to add realm database in that as well

Review Notes on Classes

  • Classes are templates for objects.

  • Javascript calls a constructor method when we create a new instance of a class.

  • Inheritance is when we create a parent class with properties and methods that we can extend to child classes.

  • We use the extends keyword to create a subclass.

  • The super keyword calls the constructor() of a parent class.

  • Static methods are called on the class, but not on instances of the class.

Library Project

Description:

Books-‘N-Stuff carries three different types of media: books, CDs, and movies. In this project, create a parent class named Media with three subclasses: Book , Movie , and CD . These three subclasses have the following properties and methods:

Book

  • Properties : author (string), title (string), pages (number), isCheckedOut (boolean, initially false ), and ratings (array, initially empty).
  • Getters : all properties have a getter
  • Methods : .getAverageRating() , .toggleCheckOutStatus() , and .addRating()

Movie

  • Properties : director (string), title (string), runTime (number), isCheckedOut (boolean, initially false ), and ratings (array, initially empty)
  • Getters : all properties have a getter
  • Methods : .getAverageRating() , .toggleCheckOutStatus() , and .addRating()

CD

  • Properties : artist (string), title (string), isCheckedOut (boolean, initially false ), and ratings (array, initially empty), songs (array of strings)
  • Getters : all properties have a getter
  • Methods : .getAverageRating() , .toggleCheckOutStatus() , and .addRating()

Code

class Media {
  constructor(title){
    this._title = title
    this._isCheckedOut = false
    this._ratings = []
  }

  get title() {
    return this._title;
  }

  get isCheckedOut() {
    return this._isCheckedOut;
  }

  get ratings(){
    return this._ratings;
  }

  set isCheckedOut(value){
    this._isCheckedOut = value
  }

  toggleCheckOutStatus() {
    this._isCheckedOut = !this._isCheckedOut;
  }

  getAverageRating() {
    let ratingsSum = this.ratings.reduce((currentSum, rating) => currentSum + rating, 0);
    const ratingLength = this.ratings.length;
    return ratingsSum/ratingLength;
  }

  addRating(rating){
    this._ratings.push(rating);
  }
}

class Book extends Media{
  constructor(title, author, pages){
    super(title)
    this._author = author
    this._pages = pages
  }

  get author() {
    return this._author
  }
  get pages() {
    return this._pages;
  }
}

class Movie extends Media{
  constructor(title, director, runtime){
    super(title)
    this._director = director
    this._runtime = runtime
  }
  get director(){
    return this._director;
  }

  get runtime(){
    return this._runtime;
  }
}

const historyOfEverything = new Book('A Short History of Nearly Everything', 'Bill Bryson', 544)

historyOfEverything.toggleCheckOutStatus()

console.log(historyOfEverything.isCheckedOut)

historyOfEverything.addRating(4)
historyOfEverything.addRating(5)
historyOfEverything.addRating(5)

console.log(historyOfEverything.getAverageRating())

const speed = new Movie('Speed', 'Jan de Bont', 116)

speed.toggleCheckOutStatus()
console.log(speed.isCheckedOut)

speed.addRating(1);
speed.addRating(1);
speed.addRating(5)

console.log(speed.getAverageRating())

I also finished Book Keeper App showing how embedded objects are created in Realm Schema and how they get synced to Atlas

Until tomorrow, :performing_arts:

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