It's like hyper-fast asynchronous event loop. I think that our brains are more like single-threaded super-computers having each task done one by one or by breaking them into smaller parts. You may argue that our brains allow us to do many things at one time, so-called multitasking. To understand this even better let's compare this process to human thinking. Very simple code illustrating basically how this never-ending event loop runs your JS code. This concept can be better understood with this piece of code: const eventLoop = Every time an iteration of this loop takes place (its called a tick) next event is run. Each event that occurs in your code (event means code that will be run) is handled by the so-called event loop. In addition, JS code is executed linearly, fragment by fragment, with each program usually consisted of at least 2 fragments (calls, functions, operations etc.). Your code runs on one thread only, thus it isn't and can't be concurrent (which is often how async is misinterpreted). JavaScript is a single-threaded language. To understand it better, we have to know some basics. We could just say that it means that something is not synchronous (running in a predefined order) but I think we can do better than that. 🎉įirst of all, let's focus on what asynchronous even mean.

I'll focus on exactly specifying what asynchronous means and ways of utilizing it in JS later on. In this article, I'll try to explain this concept in the easiest possible way so that its fundamentals should become clear once-and-for-all for everyone reading this.

While many programmers have utilized it in their code, a great number of them might not even know how it really works. One of the most important and complex aspects to understand is asynchronous programming. Only full dive in can lead to a discovery of JS complexity. This might seem to be true when looking at it without going deeper into the subject, in reality, JS is far from the easiest programming language to learn. JavaScript may seem like an easy language to start with at the beginning.

Java script basics