Introduction to React.js and JSX

A lesson for beginners that introduces the library React.js that is used to build user interfaces (UI). It's part of frontend development in the browser, although learning the way of writing React can also translate to other platforms such as mobile with React Native and virtual reality with React VR.

CodeSandbox is leveraged as the development environment, although other web-based alternatives are also available. You can also develop locally, generating the project with a tool like create-react-app.

Writing an HTML-like pattern within JavaScript is also introduced. JSX transpilation is briefly explained using the Babel website's Try it out feature.

The lesson goes on teaching how to change the view that is rendered by the React component. You learn to return multiple things from a component function using a Fragment.

Finally, you briefly see, using the browser Developer Tools (DevTools for short), how the React.js application is injected in a lone, empty div element whose id is root.