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 class vs className This lesson will cover more advanced JSX. You’ll learn some powerful tricks and some common errors to avoid. Grammar in JSX is mostly the same as in HTML, but there are subtle differences to watch out for. The most frequent of these involves the word class. In HTML, it’s common to use class as an attribute name: <h1 class = "big" > Title </h1> In JSX, you can’t use the word  class ! You have to use  className  instead: <h1 className = "big" > Title </h1> This is because JSX gets translated into JavaScript, and  class  is a reserved word in JavaScript. When JSX is  rendered , JSX  className  attributes are automatically rendered as  class  attributes. Self-Closing Tags Another common JSX error involves  self-closing tags . What’s a self-closing tag? Most HTML elements use two tags: an  opening tag  ( <div> ), and a  closing tag  ( </div> ). However, som...

React JS Commands and Useful purposes  To Install react app: npx create-react-app app-name To Install react app: npx create-react-app . To check npm version: npm --version Inside that directory, you can run several commands:   npm start     Starts the development server.   npm run build     Bundles the app into static files for production.   npm test     Starts the test runner.   npm run eject     Removes this tool and copies build dependencies, configuration files     and scripts into the app directory. If you do this, you can’t go back! node -v (To check node version)

ReactJS JSX   React is a modular, scalable, flexible, and popular front-end framework. What is JSX? JSX is a syntax extension for JavaScript. It was written to be used with React. JSX code looks a lot like HTML. What does “syntax extension” mean? In this case, it means that JSX is not valid JavaScript. Web browsers can’t read it! If a JavaScript file contains JSX code, then that file will have to be compiled. This means that before the file reaches a web browser, a JSX compiler will translate any JSX into regular JavaScript. Codecademy’s servers already have a JSX compiler installed, so you don’t have to worry about that for now. Eventually we’ll walk through how to set up a JSX compiler on your personal computer. JSX is a syntax extension for JavaScript which allows us to treat HTML as expressions. const h1 = <h1>Hello world</h1>; They can be stored in variables, objects, arrays, and more! Here’s an example of several JSX elements being stored in an object: const ...