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

Call stacks and memory allocation

Memory allocation is a necessity of any programming language. Without this, we have no data structures to work with, not even primitive types. Memory is cheap, and it seems that there's plenty of it to go around; this isn't cause for celebration just yet. While it's more feasible today to allocate larger data structures in memory then it was 10 years ago, we still have to deallocate that memory when we're done with it. JavaScript is a garbage-collected language, which means our code doesn't have to explicitly destroy objects in memory. However, the garbage collector incurs a CPU penalty.

So there are two factors in play here. We want to conserve two resources here, and we'll try to do so using generators to implement lazy evaluation. We don't want to allocate memory unnecessarily, and if we can avoid this, then we can avoid invoking the garbage collector frequently. In this section, I'll introduce some generator concepts.

Bookmarking function contexts

In a...