Book Image

JavaScript Concurrency

By : Adam Boduch
Book Image

JavaScript Concurrency

By: Adam Boduch

Overview of this book

Concurrent programming may sound abstract and complex, but it helps to deliver a better user experience. With single threaded JavaScript, applications lack dynamism. This means that when JavaScript code is running, nothing else can happen. The DOM can’t update, which means the UI freezes. In a world where users expect speed and responsiveness – in all senses of the word – this is something no developer can afford. Fortunately, JavaScript has evolved to adopt concurrent capabilities – one of the reasons why it is still at the forefront of modern web development. This book helps you dive into concurrent JavaScript, and demonstrates how to apply its core principles and key techniques and tools to a range of complex development challenges. Built around the three core principles of concurrency – parallelism, synchronization, and conservation – you’ll learn everything you need to unlock a more efficient and dynamic JavaScript, to lay the foundations of even better user experiences. Throughout the book you’ll learn how to put these principles into action by using a range of development approaches. Covering everything from JavaScript promises, web workers, generators and functional programming techniques, everything you learn will have a real impact on the performance of your applications. You’ll also learn how to move between client and server, for a more frictionless and fully realized approach to development. With further guidance on concurrent programming with Node.js, JavaScript Concurrency is committed to making you a better web developer. The best developers know that great design is about more than the UI – with concurrency, you can be confident every your project will be expertly designed to guarantee its dynamism and power.
Table of Contents (17 chapters)
JavaScript Concurrency
About the Author
About the Reviewer

Server clusters

It's one thing to scale up a single machine that's running our NodeJS application by enabling parallelism through process management. This is a great way to get the most of our physical hardware or our virtual hardware—they both cost money. However, there's an inherent limitation to scaling up just one machine—it can only go so far. At some threshold in some dimension of our scaling problems, we'll hit a wall. Before this happens, we need to think about scaling our Node application to several machines.

In this section, we'll introduce the idea of proxying our web requests to other machines instead of handling them all on the machine where they arrive. Then, we'll look at implementing microservices, and how they can help compose a sound application architecture. Finally, we'll implement some load balancing code that's tailored to our application; and how it handles requests.

Proxying requests

A request proxy in NodeJS is exactly what it sounds like. The request arrives at a server...