A structured lesson workspace with readable content, hands-on examples, and a clean path to completion.
| Question to ask | Good diagnostic move |
|---|---|
| What value entered? | Inspect the runtime value and type. |
| What rule applied? | Check the construct's language or host semantics. |
| What changed? | Compare the smallest working and failing cases. |
console.log('A');setTimeout(() => console.log('timer'), 0);queueMicrotask(() => console.log('microtask'));console.log('B');
<strong>Core idea:</strong> JavaScript execution is not just 'run the file from top to bottom.' The engine creates execution contexts, the stack tracks active calls, and the host schedules asynchronous work. In this lesson, the practical target is microtasks, macrotasks, and task queues: you should be able to predict what the runtime will do before changing the code.
<strong>Core idea:</strong> JavaScript execution is not just 'run the file from top to bottom.' The engine creates execution contexts, the stack tracks active calls, and the host schedules asynchronous work. In this lesson, the practical target is microtasks, macrotasks, and task queues: you should be able to predict what the runtime will do before changing the code.
Mentor note: for microtasks, macrotasks, and task queues, name the invariant you need before reaching for a clever shortcut. Clear state and explicit assumptions make later debugging much cheaper.
Finish the lesson once you have worked through the material. This awards ★ 20 XP.