Object Oriented Programming and classes

class Book {
  constructor(title) {
    this.title = title;
    this.available = true;
  }

  describe() {
    return `${this.title} is the title of the book`;
  }

  borrow() {
    this.available = false;
  }

  // static method
  static isEven(number) {
    return number % 2 === 0;
  }
}

const book = new Book("new title");
console.log(book.describe());
book.borrow();
console.log(book.available);     // false
console.log(Book.isEven(4));     // true

class Book:
    def __init__(self, title):   # constructor
        self.title = title
        self.available = True    # capital True

    def describe(self):  # every method gets `self` first
        return f"{self.title} is the title of the book"

    def borrow(self):
        self.available = False

    @staticmethod
    def is_even(number):   # no self
        return number % 2 == 0


book = Book("new title")  # no `new` keyword
print(book.describe())
book.borrow()
print(book.available)   # False
print(Book.is_even(4))  # True

class BookDetails extends Book {
  constructor(title, author) {
    super(title);                // pass args to parent
    this.author = author;
  }

  printDetails() {
    return `${this.title} is written by ${this.author}`;
  }
}

const bd = new BookDetails("light bulb", "Edison");
console.log(bd.printDetails());  
// "light bulb is written by Edison"

class BookDetails(Book):
    def __init__(self, title, author):
        super().__init__(title)   # super() takes NO args itself; 
                                  # call __init__ on it
        self.author = author

    def print_details(self):
        return f"{self.title} is written by {self.author}"


bd = BookDetails("light bulb", "Edison")
print(bd.print_details())          # "light bulb is written by Edison"

# For JS devs: the two things that feel weird at first are 
# (1) passing `self`
# to every method and 
# (2) __init__ as the constructor name. 
# Everything else maps 1:1.