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

What is a function?

Functions allow you to group together a code, give it a name, and reuse it later, addressing it by the name you gave it. Let's consider the following code as an example:

    function sum(a, b) { 
      var c = a + b; 
      return c; 

The parts that make up a function are shown as follows:

  • The function keyword.

  • The name of the function; in this case, sum.

  • The function parameters; in this case, a and b. A function can take any number of parameters, or no parameters, separated by commas.

  • A code block, also called the body of the function.

  • The return statement. A function always returns a value. If it doesn't return a value explicitly, it implicitly returns the value undefined.

Note that a function can only return a single value. If you need to return more values, you can simply return an array that contains all of the values you need as elements of this array.

The preceding syntax is called a function declaration. It's just one of the ways to create a...