The event loop is a critical part of JavaScript’s runtime, enabling asynchronous programming. Here’s a simple example:

console.log('Start')

setTimeout(() => {
  console.log('Timeout')
}, 0)

console.log('End')

Output:

Start
End
Timeout

The event loop ensures that the call stack is empty before executing tasks from the callback queue. This mechanism allows JavaScript to handle asynchronous operations efficiently.

node -e "console.log('Start'); setTimeout(() => { console.log('Timeout'); }, 0); console.log('End');"