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 baseUrl = process.env.API_BASE_URL ?? 'http://localhost:3000';console.log(baseUrl);
This example demonstrates environment-specific configuration 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.
This example demonstrates environment-specific configuration 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.
A common failure with environment-specific configuration is changing several variables at once. That hides which rule actually caused the result.
Finish the lesson once you have worked through the material. This awards ★ 20 XP.