kay-is/react-from-zero

React From Zero is a beginner tutorial series for learning React, the JavaScript library used to build user interfaces. The distinguishing feature is that each lesson is a single HTML file that runs directly in a web browser, with no build tools, no command-line setup, and no pre-compilation step required. You just open the file and it works. The README describes it as "99% ES2015 less," meaning the examples avoid most modern JavaScript syntax that typically requires extra tooling to understand or run. The tutorial has 18 lessons, each building on the previous one. It starts at the most basic level, showing what a React element actually is as a plain JavaScript object, then walks through how to create elements with code, introduces JSX (the HTML-like syntax React developers commonly use), and progressively covers components, passing data between components, nested structures, and component classes. Later lessons cover lifecycle methods (code that runs at specific moments in a component's life, like when it first appears on screen), how to connect React to other JavaScript libraries, and how to write unit tests. Because each lesson is a standalone HTML file, you can preview any of them directly in a browser from the GitHub Pages links listed in the README. No cloning the repository is required to follow along. If you want to move the examples into a standard React project created with the official tooling, the README explains how to copy the relevant script sections into the appropriate file. Translations of the tutorial exist in Chinese, Brazilian Portuguese, Russian, Spanish, and Korean, each maintained as a separate repository. The project is linked to a book, "Fullstack React," though the tutorial itself is free and self-contained.