Learn React

What you will practise

Build React interfaces by splitting the screen into components. Connect props, events and state to create understandable interactions.

• Compose interfaces with JSX and props.
• Update state with useState.
• Understand effects and their cleanup.

Before you start: You should understand JavaScript functions, objects and arrays. The JavaScript course covers these foundations.

A first example to understand

function Welcome({ name }) {
  return <p>Bonjour {name} !</p>;
}

export default function App() {
  return <Welcome name="Carthago" />;
}

Welcome is a component. Its name prop personalises the message without duplicating the component. Braces insert JavaScript values into JSX.

Try it: Render two Welcome components with different names in your React application.

Understand a specific concept

• Complete Guide to React Hooks: useState & useEffect (React 19)