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 working with express.js and change one assumption at a time.
Keep the experiment focused on working with express.js and change one assumption at a time.
This example demonstrates working with express.js directly. Change one input at a time and observe the result; the goal is to connect the syntax to the runtime behavior rather than treating the snippet as a recipe.
Finish the lesson once you have worked through the material. This awards ★ 20 XP.