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

From arrays to objects

As you already know from Chapter 2, Primitive Data Types, Arrays, Loops, and Conditions, an array is just a list of values. Each value has an index (a numeric key) that starts from zero and increments by one for each value. Consider the following example:

    > var myarr = ['red', 'blue', 'yellow', 'purple']; 
    > myarr; 
    ["red", "blue", "yellow", "purple"]. 
    > myarr[0]; 
    > myarr[3]; 

If you put the indexes in one column and the values in another, you'll end up with a table of key/value pairs shown as follows:











An object is similar to an array, but the difference is that you define the keys yourself. You're not limited to using only numeric indexes, and you can use friendlier keys such as first_name, age, and so on.

Let's take a look at a simple object and examine its parts:

    var hero = { 
      breed: 'Turtle',