How does the Event Loop work — what queues are there, and what is their execution order? Tell about microtasks, macrotasks, requestAnimationFrame, requestIdleCallback.

Event Loop — is a mechanism in JavaScript that allows processing asynchronous operations without blocking the main thread.

Main queues:

• Macro task queue: setTimeout, setInterval, I/O, UI events.
• Microtask queue: Promise.then/catch/finally, MutationObserver.

Execution order:

1. One macro task is executed from the queue.
2. After that, all microtasks from the microtask queue are executed.
3. The rendering is updated (if needed).
4. Move to the next macro task.

requestAnimationFrame — is an API for scheduling a function for the next animation frame, called before repaint.

requestIdleCallback — allows scheduling a function to run when the browser is idle, i.e., during idle periods, to avoid interfering with main tasks.

Thus, the Event Loop ensures smooth interface performance and efficient execution of asynchronous code.