Book Image

Mastering JavaScript Object-Oriented Programming

Book Image

Mastering JavaScript Object-Oriented Programming

Overview of this book

ECMAScript 6 introduces several new Object-Oriented features that drastically change the way developers structure their projects. Web developers now have some advanced OOP functionality at their disposal to build large-scale applications in JavaScript. With this book, we'll provide you with a comprehensive overview of OOP principles in JavaScript and how they can be implemented to build sophisticated web applications. Kicking off with a subtle refresher on objects, we'll show you how easy it is to define objects with the new ES6 classes. From there, we'll fly you through some essential OOP principles, forming a base for you to get hands-on with encapsulation. You'll get to work with the different methods of inheritance and we'll show you how to avoid using inheritance with Duck Typing. From there, we'll move on to some advanced patterns for object creation and you'll get a strong idea of how to use interesting patterns to present data to users and to bind data. We'll use the famous promises to work with asynchronous processes and will give you some tips on how to organize your code effectively. You'll find out how to create robust code using SOLID principles and finally, we'll show you how to clearly define the goals of your application architecture to get better, smarter, and more effective coding. This book is your one-way ticket to becoming a JavaScript Jedi who can be counted on to deliver flexible and maintainable code.
Table of Contents (18 chapters)
Mastering JavaScript Object-Oriented Programming
Credits
About the Author
About the Reviewer
www.PacktPub.com
Preface

Creating a singleton


Sometimes, we may need to have a single occurrence of an object throughout the application life. Consider, for example, a configuration manager or a cache manager. Since they provide a global point of access to an internal or external resource, they need to be implemented in a way so that only one instance must exist, that is, they need to be implemented as a singleton.

The singleton pattern is one of the simplest design patterns—it involves only one entity which is responsible for making sure it creates not more than one instance and provides a global point of access to itself. For a class-based language, this means that a class can be instantiated only one time and any attempt to create a new instance of the class returns the instance already created.

In JavaScript, we can create objects through the literal notation, so any such object is already a singleton:

var johnSingleton = { 
    name: "John", 
    surname: "Singleton" 
}; 

So, why do we need to implement this design...