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

Types of workers

There are three types of web workers that we're likely to encounter during the development of concurrent JavaScript applications. In this section, we'll compare the three types so that we can understand which type of worker makes sense in any given context.

Dedicated workers

Dedicated workers are probably the most common worker type. They're considered the default type of web worker. When our page creates a new worker, it's dedicated to the page's execution context and nothing else. When our page goes away, so do all the dedicated workers created by the page.

The communication path between the page and any dedicated worker that it creates is straightforward. The page posts messages to the workers, which in turn post messages back to the page. The exact orchestration of these messages is dependent on the problem that we're trying to solve using web workers. We'll dig into more of these messaging patterns throughout the book.


The terms main thread and page are synonymous in...