A structured lesson workspace with readable content, hands-on examples, and a clean path to completion.
| Observation | Diagnostic question |
|---|---|
| Runtime value | What value actually arrived? |
| Language rule | Which rule determines the result? |
const start = performance.now();for (let i = 0; i < 100_000; i += 1) Math.sqrt(i);console.log(`elapsed: ${(performance.now() - start).toFixed(2)}ms`);
Keep the experiment focused on javascript performance fundamentals and change one assumption at a time.
Keep the experiment focused on javascript performance fundamentals and change one assumption at a time.
Mentor note: for javascript performance fundamentals, 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.