Book Image

Node.js Design Patterns - Second Edition

By : Luciano Mammino, Purra, Mario Casciaro
Book Image

Node.js Design Patterns - Second Edition

By: Luciano Mammino, Purra, 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 (12 chapters)

Template


The next pattern that we are going to analyze is called Template and it also has a lot in common with the Strategy pattern. Template consists of defining an abstract pseudo class that represents the skeleton of an algorithm, where some of its steps are left undefined. Subclasses can then fill the gaps in the algorithm by implementing the missing steps, called template methods. The intent of this pattern is to make it possible to define a family of classes that are all variations of a similar algorithm. The following UML diagram shows the structure that we just described:

The three concrete classes shown in the previous diagram, extend Template and provide an implementation for templateMethod(), which is abstract or pure virtual, to use the C++ terminology; in JavaScript this means that the method is left undefined or is assigned to a function that always throws an exception, indicating the fact that the method has to be implemented. The Template pattern can be considered more classically...