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


In this chapter, we introduced the concept of parallel execution using web workers. Before web workers, there were no means for our JavaScript to utilize the multiple CPU cores found on most hardware today.

We started off with a high-level overview of what web workers are. They're operating-system-level threads at their foundation. From a JavaScript perspective, they're event targets where we can post messages and listen to message events. Workers come in three varieties—dedicated, shared, and sub-workers.

You then learned how to communicate with web workers by posting messages and listening to events. You learned that there's a limitation in place in terms of what can be passed in a message. This is due to the fact that all message data is serialized and reconstructed in the target thread.

We wrapped up the chapter with a look at how to go about handling errors and exceptions in web workers. In the following chapter, we'll address the practical aspects of parallelization—the types...