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. |
function* ids() {yield 101;yield 102;}const iterator = ids();console.log(iterator.next(), iterator.next());
<strong>Core idea:</strong> Modern JavaScript added syntax and language tools that make common patterns easier to express. The important question is still whether a feature makes the code clearer and safer. In this lesson, the practical target is iterators and generators: you should be able to predict what the runtime will do before changing the code.
<strong>Core idea:</strong> Modern JavaScript added syntax and language tools that make common patterns easier to express. The important question is still whether a feature makes the code clearer and safer. In this lesson, the practical target is iterators and generators: you should be able to predict what the runtime will do before changing the code.
Mentor note: for iterators and generators, 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.