Each lesson points you to the right reference page with specific things to look for. The Codex pages are the lessons — structured guidance, real code, official sources.
Track 1
Foundations
Your first JavaScript programs
- What JavaScript is and how to run it
- Variables, types, and coercion
- Control flow and loops
- Functions and scope
- Arrays, objects, and destructuring
Track 2
Practitioner
Build real web pages
- The DOM and events
- Async JavaScript and Promises
- async/await and error handling
- OOP and classes
- Modules (ESM)
Track 3
Advanced
Think like a JS developer
- Closures and the event loop internals
- Prototype chain and class internals
- Iterators, generators, Symbol
- Proxy and Reflect
- TypeScript introduction
After the tracks
Move to TypeScript — everything you just learned transfers directly, and you gain a type system on top.
TypeScript Reference →