1console.log("Start");
2
3setTimeout(() => {
4    console.log("Timeout");
5}, 0);
6
7Promise.resolve().then(() => {
8    console.log("Promise");
9});
10
11console.log("End");
12

What is JavaScript Event Loop?

The event loop is a core concept in JavaScript that allows it to be non-blocking and asynchronous. It is a mechanism that handles the execution of code, managing the call stack, callback queue, and other components to ensure that asynchronous operations are handled properly.

In simple terms, the event loop is a continuous process that checks if there is any code to execute and, if so, executes it. It is a fundamental part of JavaScript's ability to handle asynchronous operations, such as network requests, timers, and user interactions, without blocking the main thread.

The event loop works by continuously monitoring the call stack and the callback queue. If the call stack is empty, it checks the callback queue for any pending callbacks. If there are any, it moves them to the call stack for execution.