How does the event loop work in JavaScript, and why is it important for asynchronous programming?

Question

JavaScript runs on a single-threaded engine—meaning it can only do one thing at a time. But thanks to the event loop, it feels non-blocking and asynchronous. Here's the process in action:

Call Stack This is where your code is executed, line by line. Functions are pushed and popped from the stack as they’re called and completed.

Web APIs / Task Queue When functions like setTimeout(), fetch(), or DOM events are encountered, they’re handed off to the browser (or Node.js APIs) to be handled in the background.

Callback Queue Once those tasks are done (like a timer finishing or a server response arriving), their callbacks are queued here.

Event Loop Cycle The event loop keeps checking:

Is the call stack empty?

If yes → it takes the first task from the callback queue and pushes it onto the stack to be executed.

Answer 1

Great info. But if you answered your own question, why post it?