Understanding Asynchronous JavaScript

Asynchronous programming is the backbone of modern JavaScript, especially in back-end development with Node.js. In Express.js applications, handling asynchronous tasks—like reading files, querying databases, and making API calls—is crucial to keeping the main execution thread unblocked and responsive.

JavaScript achieves this with its event-driven, non-blocking architecture. But what does that look like in practice? Before we get into the details, let’s explore a simple example of JavaScript’s non-blocking behavior.