Book Image

Object-Oriented JavaScript - Third Edition

By : Ved Antani, Stoyan STEFANOV
5 (1)
Book Image

Object-Oriented JavaScript - Third Edition

5 (1)
By: Ved Antani, Stoyan STEFANOV

Overview of this book

JavaScript is an object-oriented programming language that is used for website development. Web pages developed today currently follow a paradigm that has three clearly distinguishable parts: content (HTML), presentation (CSS), and behavior (JavaScript). JavaScript is one important pillar in this paradigm, and is responsible for the running of the web pages. This book will take your JavaScript skills to a new level of sophistication and get you prepared for your journey through professional web development. Updated for ES6, this book covers everything you will need to unleash the power of object-oriented programming in JavaScript while building professional web applications. The book begins with the basics of object-oriented programming in JavaScript and then gradually progresses to cover functions, objects, and prototypes, and how these concepts can be used to make your programs cleaner, more maintainable, faster, and compatible with other programs/libraries. By the end of the book, you will have learned how to incorporate object-oriented programming in your web development workflow to build professional JavaScript applications.
Table of Contents (25 chapters)
Object-Oriented JavaScript - Third Edition
About the Authors
About the Reviewer
Customer Feedback
Built-in Functions
Regular Expressions

Case study - drawing shapes

Let's finish off this chapter with a more practical example of using inheritance. The task is to be able to calculate the area and the perimeter of different shapes, as well as to draw them, while reusing as much code as possible.


Let's have one Shape constructor that contains all the common parts. From there, let's have Triangle, Rectangle, and Square constructors, all inheriting from Shape. A square is really a rectangle with the same length sides, so let's reuse Rectangle when building Square.

In order to define a shape, you'll need points with x and y coordinates. A generic shape can have any number of points. A triangle is defined with three points, a rectangle (to keep it simpler) with one point and the lengths of the sides. The perimeter of any shape is the sum of its side's lengths. Calculating the area is shape specific and will be implemented by each shape.

The common functionality in Shape would be:

  • A draw() method that can draw any shape given...