JavaScript yana gudu akan **zafi guda", saboda haka yana iya yin aikin ɗaya ne a lokaci. event loop shine abin da ya bashi iya yin gaggawar asynchronous ba tare da katsewar ajiya ba: yana gudu call stack, kuma lokacin da stack ya zama fanila, yana ja callbacks daga cibiyoyi.
Akwai cibiya biyu masu nisbos daban-daban:
.then), queueMicrotask. Ana suliri gaba daya bayan kowe aikin, kafin zane.setTimeout, I/O, UI events. Ana yin sa na ɗaya a jigilar loop.console.log("1"); // sync
setTimeout(() => console.log("2"), 0); // macrotask
Promise.resolve().then(() => console.log("3")); // microtask
console.log("4"); // sync
// Output: 1, 4, 3, 2
1, 4.3.2.Wan shine dalilin da Promise.then koyaushe yana gudu kafin setTimeout(…, 0), ko da duka jama'a ne "async" — microtasks suna da gidiya.
// ❌ blocks the single thread — UI freezes for 5 seconds
while (Date.now() - start < 5000) {}
Lambar doguwa na yau da kullun tana tabbata da komai (zane, kujerun). Dora aikace-aikacen CPU mai nauyi zuwa Web Worker (zafi ta gaske na daban).
Sanin loop yana bayyana tsari na asynchronous, me ya sababbi alkawari sun kunna kafin timers, kuma me ya sababbi kada ki katse zafi na kansu— tsarin tunani na asali don duk asynchronous JavaScript.