At this point in your JavaScript journey, you have probably heard that JavaScript is a single-threaded language. This is correct; JavaScript is a single-threaded language that executes code sequentially. This means that only one block of code can be running at a time in the JavaScript runtime environment (we will be using V8 as our example environment). The synchronous nature of JavaScript can lead to an issue aptly called “blocking” when a slow operation is running.

As a modern JavaScript developer, this may make you stop in your tracks once you think about what is happening in the apps you…