Rediscovering JavaScript

Chapter 7

Here are the solutions to the ​Exercises​, for the Chapter 7, ​Working with Classes​ chapter.

Exercise 1

'use strict';

class Book {
  constructor(title, author, pages) {
    this.title = title;
    this.author = author;
    this.numberOfPages = pages;
    this.sales = 0;
  }

  get pages() { return this.numberOfPages; }

  get copiesSold() { return this.sales; }
  set copiesSold(value) {
    if(value < 0) throw new Error(`Value can't be negative`);

    this.sales = value;
  }
}

const book = new Book('Who Moved My Cheese?', 'Spencer Johnson', 96);
console.log(book.title); //Who Moved My Cheese
console.log(book.pages); //96

try {
  book.pages = 96;
} catch(ex) {
 console.log(ex.message); ...