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

Chapter 5. Working with Workers

Web workers enable true parallelism within a web browser. They've spent time maturing, and have pretty good vendor support today. Before web workers, our JavaScript code was confined to the CPU, where our execution environment started when the page first loaded. Web workers have evolved out of necessity—web applications are growing more capable. They have also started to require more compute power. At the same time, multiple CPU cores are common place today—even on low-end hardware.

In this chapter, we'll walk through the conceptual ideas of web workers, and how they relate to the concurrency principles that we're trying to achieve in our applications. Then, you'll learn how to use web workers by example, so that, later on in the book, we can start tying parallelism to some of the other ideas that we've already explored, such as promises and generators.