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

Copying properties

Now, let's try a slightly different approach. Since inheritance is all about reusing code, can you simply copy the properties you like from one object to another? Or from a parent to a child? Keeping the same interface as the preceding extend() function, you can create a extend2()function, which takes two constructor functions and copies all the properties from the parent's prototype to the child's prototype. This will, of course, carry over methods too, as methods are just properties that happen to be functions:

    function extend2(Child, Parent) { 
      var p = Parent.prototype; 
      var c = Child.prototype; 
      for (var i in p) { 
        c[i] = p[i]; 
      c.uber = p; 

As you can see, a simple loop through the properties is all it takes. As with the previous example, you can set an uber property if you want to have handy access to parent's methods from the child. Unlike the previous example though, it's...