What Is JSX?

JSX is a syntax extension that adds HTML-like syntax to JavaScript. It lets developers describe user interfaces in a more intuitive and readable way, acting as a bridge between JavaScript and HTML when defining the structure of React components.

Key features of JSX:

1. HTML-like syntax: JSX looks like HTML, so building interfaces feels like writing HTML tags.

2. JavaScript expressions: Any JavaScript expression can be used inside JSX by wrapping it in {}, which makes dynamic content easy to show.

3. Component structure: JSX describes the structure of React components, and components themselves can be used in JSX like HTML tags.

4. Attributes and events: JSX supports attributes (props) and events, so you can pass data to components and handle user interaction.

5. Readability and maintenance: Keeping a component's structure and behaviour in one place makes the code easier to read and maintain.

A simple JSX example:

const element = <h1>Hello, world!</h1>;

This is a JSX expression containing the text "Hello, world!" in an h1 heading. JSX is only a syntax: browsers cannot run it directly, so before a React application is published, a compiler (usually Babel) turns it into plain JavaScript.