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? |
import express from 'express';const app = express();app.use(express.json());app.get('/health', (_req, res) => res.json({ ok: true }));app.listen(3000);
Keep the experiment focused on nested conditions and complex logical expressions and change one assumption at a time.
A useful habit here is to inspect the actual value or runtime state rather than trusting a name. The example below is intentionally small, so one changed line has an obvious effect.
Finish the lesson once you have worked through the material. This awards ★ 20 XP.