Difference between macrotask queue and microtask queue

JavaScript has two queues:

Macrotask queue / Task queue

• Big tasks like setTimeout, events.
• Includes callbacks from setTimeout, setInterval, setImmediate (Node), I/O, DOM events.
• The event loop processes one macrotask, then checks microtasks.

Microtask queue

• Smaller, high-priority tasks like promises.
• Includes callbacks from Promise.then/catch/finally, queueMicrotask, MutationObserver.
• The event loop drains all microtasks before handling the next macrotask.

Priority: microtasks are higher priority, so they run before the next task.