Book Image

Node.js Design Patterns

By : Mario Casciaro
Book Image

Node.js Design Patterns

By: 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 fundamental principles and components that define the platform. It then shows you how to master asynchronous programming and how to design elegant and reusable components using well-known patterns and techniques. The book rounds off by teaching you the various approaches to scale, distribute, and integrate your Node.js application.
Table of Contents (16 chapters)
Node.js Design Patterns
Credits
About the Author
Acknowledgments
About the Reviewers
www.PacktPub.com
Preface
Index

Running CPU-bound tasks


The totalSales() API, even though expensive in terms of resources, was not affecting the ability of the server to accept concurrent requests. What we learned in Chapter 1, Node.js Design Fundamentals, about the event loop should provide an explanation for this behavior: invoking an asynchronous operation causes the stack to unwind back to the event loop, leaving it free to handle other requests.

However, what happens when we run a long, synchronous task that never gives back the control to the event loop? This kind of task is also known as CPU-bound, because its main characteristic is that it is heavy on CPU utilization rather than being heavy on I/O operations.

Let's work immediately on an example to see how these types of tasks behave in Node.js.

Solving the subset sum problem

Let's now choose a computationally expensive problem to use as a base for our experiment. A good candidate is the subset sum problem that consists of deciding whether a set (or multiset) of integers...