Book Image

Node.js Design Patterns - Second Edition

By : Joel Purra, Luciano Mammino, Mario Casciaro
Book Image

Node.js Design Patterns - Second Edition

By: Joel Purra, Luciano Mammino, Mario Casciaro

Overview of this book

Node.js is a massively popular software platform that lets you use JavaScript to easily create scalable server-side applications. It allows you to create efficient code, enabling a more sustainable way of writing software made of only one language across the full stack, along with extreme levels of reusability, pragmatism, simplicity, and collaboration. Node.js is revolutionizing the web and the way people and companies create their software. In this book, we will take you on a journey across various ideas and components, and the challenges you would commonly encounter while designing and developing software using the Node.js platform. You will also discover the "Node.js way" of dealing with design and coding decisions. The book kicks off by exploring the basics of Node.js describing it's asynchronous single-threaded architecture and the main design patterns. It then shows you how to master the asynchronous control flow patterns,and the stream component and it culminates into a detailed list of Node.js implementations of the most common design patterns as well as some specific design patterns that are exclusive to the Node.js world.Lastly, it dives into more advanced concepts such as Universal Javascript, and scalability' and it's meant to conclude the journey by giving the reader all the necessary concepts to be able to build an enterprise grade application using Node.js.
Table of Contents (20 chapters)
Node.js Design Patterns - Second Edition
Credits
About the Authors
Acknowledgments
About the Author
Acknowledgments
About the Reviewers
www.PacktPub.com
Preface

Strategy


The Strategy pattern enables an object, called the Context, to support variations in its logic by extracting the variable parts into separate, interchangeable objects called Strategies. The context implements the common logic of a family of algorithms, while a strategy implements the mutable parts, allowing the context to adapt its behavior depending on different factors such as an input value, a system configuration, or user preferences. The strategies are usually part of a family of solutions and all of them implement the same interface, which is the one that is expected by the context. The following figure shows the situation we just described:

The preceding figure shows how the context object can plug different strategies into its structure, as if they were replaceable parts of a piece of machinery. Imagine a car; its tires can be considered its strategy for adapting to the different road conditions. We can fit winter tires to go on snowy roads thanks to their studs, while...