About

About the course

Hi, I'm Zdeněk Grežďo and I program in my free time. I wrote the course as a study aid for myself – and I'll be glad if it helps you too.

How it came about

I wanted to understand React properly – not just to know what to write, but why it works the way it does and when to use what. So I started writing explanations in my own words, with analogies from everyday life, examples I could click through and small challenges to check I really got it.

Over time it grew into a whole course: from the JavaScript React needs to routing, data fetching and state management. When I saw how much it helped me, I decided to share it. It is free and will stay free.

Claude, an AI assistant by Anthropic, helped me write it – the lesson texts, demos, challenges, the English translation, the tests and the code of the whole site.

What you'll find here

27 lessons with live demos and analogies instead of dry theory
69 challenges solved right in the browser, from warm-ups to hard ones
quizzes with spaced review, a placement test and cheat sheets

Found a mistake or have an idea?

I'm a hobby programmer, not a professional author, so mistakes can slip in. Every lesson has a feedback form at the end – I read every message. You can also write to zg.programm@gmail.com. How your data is handled: Privacy.