May 17, 2024 · Understanding how event loop works is important for optimizations, and sometimes for the right architecture. In this chapter we first cover theoretical details about how things work, and …

Sep 18, 2014 · Separation of macro and microtask enables the event loop to prioritize types of tasks; for example, giving priority to performance-sensitive tasks. In a single loop iteration, one macro task at …

Jan 25, 2023 · Micro-tasks are often scheduled for things that are required to be completed immediately after the execution of the current script. On completion of one macro-task, the event loop moves on …

Jan 13, 2026 · At the heart of how JavaScript handles asynchronous operations lies the event loop — and within it, two distinct queues that determine execution priority: the microtask queue and the...

Learn the difference between microtasks and macrotasks in JavaScript, how the event loop schedules them, and how they affect async behavior.

Nov 25, 2025 · JavaScript utilizes a single main thread of execution coupled with a sophisticated mechanism known as the Event Loop. It can only do one thing at a time. Here is the flow you need to …

Sep 20, 2025 · Each turn of the browser loop runs one macrotask (e.g., setTimeout, event), then flushes microtasks (e.g., Promise.then, queueMicrotask), then may render a frame.