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


The previous chapter introduced us to web workers, highlighting the powerful capabilities of these components. This chapter shifted gears and focused on the "why" aspect of parallelism. We kicked things off by looking at some aspects of functional programming, and how they lend themselves to concurrent programming in JavaScript.

We looked at the factors involved in determining the viability of executing a given operation concurrently across workers. Sometimes, there's a lot of overhead involved with taking apart a large task and distributing it to workers as smaller tasks. We implemented some generic utilities that can help us with the implementation of concurrent functions, encapsulating some of the associated concurrency boilerplate.

Not all problems are well-suited for a concurrent solution. The best approach is to work top-down, seeking out the embarrassingly-parallel problems as they're the low-hanging fruit. We then applied this principle to a number of map-reduce problems.