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

Worker communication with promises

We now have a handle on why treating primitive values as promises benefits our code. It's time to apply this concept to web workers. In the preceding two chapters, our code that synchronized responses coming from web workers started to look a little intractable. This was because we were essentially trying to emulate many boilerplate chores that promises are good at handling. We'll first attempt to solve these problems by creating helper functions that wrap the worker communications for us, returning promises. Then we'll try another approach that involves extending the web worker interface at a lower level. Lastly, we'll look at some more complex synchronization scenarios that involve multiple workers, such as those from the last chapter.

Helper functions

It would be ideal if we could get web worker responses back in the form of a promise resolution. But, we need to create the promise in the first place—how do we do this? Well, we could manually create the...