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
About the Authors
About the Author
About the Reviewers

Revealing constructor

The revealing constructor pattern is a relatively new pattern that is gaining traction in the Node.js community and in JavaScript, especially because it's used within some core libraries such as Promise.

We have already implicitly seen this pattern in Chapter 4, Asynchronous Control Flow Patterns with ES2015 and Beyond, while exploring promises, but let's get back to it and analyze the Promise constructor to embrace it in greater detail:

const promise = new Promise(function (resolve, reject) { 
  // ... 

As you can see, Promise accepts a function as a constructor argument, which is called the executor function. This function is called by the internal implementation of the Promise constructor and it is used to allow the constructing code to manipulate only a limited part of the internal state of the promise under construction. In other words, it serves as a mechanism to expose the resolve and reject functions so that they can be invoked to change the...