Microtasks vs Macrotasks (Promises vs Timers)

Microtask Queue

Microtasks run immediately after the current call stack completes, before the event loop proceeds to the next phase.

Promise Example

Promise.resolve().then(() => console.log('microtask'));
setTimeout(() => console.log('timeout'), 0);

Order

The promise callback runs before the timeout callback.

process.nextTick

process.nextTick runs even before other microtasks and should be used carefully to avoid starvation.

Production Insight

Overusing microtasks can delay I/O callbacks and reduce responsiveness.