Microtask Queue

> **Microtask Queue** (a.k.a. Job Queue or Promise Jobs)

Microtasks are higher-priority tasks that run **immediately after the current script finishes**, **before** any macrotasks.

# Examples: * `Promise.then` * `Promise.catch` * `Promise.finally` * `queueMicrotask()` * `MutationObserver` (used internally by frameworks like Vue)

# Execution Order: 1. Run current stack to completion. 2. Run **all microtasks** in order. 3. Only then pick the next macrotask.

> This is why `Promise.then()` callbacks can **appear to jump ahead** of `setTimeout` calls, even with `setTimeout(..., 0)`.