Composing components

What this means

Composition means building a larger UI by placing components inside other components. A page might use Header, Sidebar, LessonCard, and Footer components together.

In beginner terms, this topic answers one practical question: "What should I write, and why does React care about it?" Do not try to memorize the syntax first. First understand the idea, then connect the syntax to that idea.

Why it matters

Composition is how React apps stay organized. You can improve one component without rewriting the whole page.

When you build real React screens, this idea helps you decide where data should live, what the user should see, and what should happen after an interaction. That is why this lesson is part of the main path instead of being an optional detail.

Step by step

1. Notice the UI problem this topic solves. 2. Look at the smallest possible example. 3. Change one value and predict what should appear. 4. Run the example and compare the result with your prediction. 5. Use the practice task before moving on.

Small example

function App() {
  return <main><Header /><LessonCard /></main>;
}

Common mistake

Do not put every part of a page into one huge component. Split when a section has a clear name or repeated structure.

Practice task

Create Header, Lesson, and App components. Render Header and Lesson inside App.

Remember this

React apps grow by composing small components.