Languages / Knowledge library
JavaScript
the language of the browser (and beyond)
Why learn JavaScript?
The only language browsers natively run. Whether you love it or not, the entire frontend ecosystem and half the backend world sits on it.
Where it came from
Written in 10 days to add interactivity to Netscape. Standardized as ECMAScript; ES6 (2015) modernized it, and Node.js took it to the server.
Build your understanding
Work through these exercises in order. Try the task before opening a reference.
- Explain var vs let vs const with examples.
- Implement debounce from scratch.
- Use fetch + async/await to render an API's data.
- Explain the event loop; predict output of a setTimeout/promise quiz.
- Build a small SPA router with history API, no framework.
Documentation and sources
- Official documentation / standards body (tc39.es)