React uses a special syntax that resembles HTML to declare components. This markup, called JSX, is embedded in the component JavaScript and needs to be compiled to JavaScript before it's usable by the browser.

The most common approach is to use Babel—a JavaScript compiler—along with a JSX plugin:

The trick is finding a way to make this compilation step as seamless as possible. As a developer, you shouldn't need to concern yourself with the JavaScript output produced by Babel.