JavaScript Event Loop: How it Works and Why it Matters

In this illustration:
The script starts with the message 'Start of the script'.
The setTimeout function is used to create an asynchronous operation. The callback inside setTimeout is pushed to the event queue after a delay of 0 milliseconds (in practice, it might not be exactly 0 due to how the browser/runtime handles it).
The script continues to execute, printing 'End of the script'.
Now, the event loop takes the callback from the event queue and executes it, printing 'Inside setTimeout callback'.
Additionally, the script includes a Promise example to illustrate another asynchronous operation. The Promise constructor is used to create a promise that resolves after a simulated delay of 2000 milliseconds. The then method is then used to handle the resolved value.
Understanding the event loop helps in dealing with asynchronous operations and ensures that code behaves as expected in various scenarios.