Client components

What this means

A client component begins with use client and can use state, effects, event handlers, and browser APIs.

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

Keeping client boundaries small improves performance while still allowing rich interaction.

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

"use client";

function Counter() {
  const [count, setCount] = useState(0);
}

Common mistake

Do not mark an entire page client-side just because one small button needs state.

Practice task

Separate a static lesson page from one interactive completion button.

Remember this

Use client components for interaction, not by default.