| --- |
| title: use client |
| description: Learn how to use the use client directive to render a component on the client. |
| --- |
|
|
| The `'use client'` directive declares an entry point for the components to be rendered on the **client side** and should be used when creating interactive user interfaces (UI) that require client-side JavaScript capabilities, such as state management, event handling, and access to browser APIs. This is a React feature. |
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| > **Good to know:** |
| > |
| > You do not need to add the `'use client'` directive to every file that contains Client Components. You only need to add it to the files whose components you want to render directly within Server Components. The `'use client'` directive defines the client-server [boundary](https://nextjs.org/docs/app/building-your-application/rendering |
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| |
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| To declare an entry point for the Client Components, add the `'use client'` directive **at the top of the file**, before any imports: |
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| ```tsx filename="app/components/counter.tsx" highlight={1} switcher |
| 'use client' |
| |
| import { useState } from 'react' |
| |
| export default function Counter() { |
| const [count, setCount] = useState(0) |
| |
| return ( |
| <div> |
| <p>Count: {count}</p> |
| <button onClick={() => setCount(count + 1)}>Increment</button> |
| </div> |
| ) |
| } |
| ``` |
|
|
| ```jsx filename="app/components/counter.js" highlight={1} switcher |
| 'use client' |
| |
| import { useState } from 'react' |
| |
| export default function Counter() { |
| const [count, setCount] = useState(0) |
| |
| return ( |
| <div> |
| <p>Count: {count}</p> |
| <button onClick={() => setCount(count + 1)}>Increment</button> |
| </div> |
| ) |
| } |
| ``` |
|
|
| When using the `'use client'` directive, the props of the Client Components must be [serializable](https://react.dev/reference/rsc/use-client |
|
|
| ```tsx filename="app/components/counter.tsx" highlight={4} switcher |
| 'use client' |
| |
| export default function Counter({ |
| onClick /* ❌ Function is not serializable */, |
| }) { |
| return ( |
| <div> |
| <button onClick={onClick}>Increment</button> |
| </div> |
| ) |
| } |
| ``` |
|
|
| ```jsx filename="app/components/counter.js" highlight={4} switcher |
| 'use client' |
| |
| export default function Counter({ |
| onClick /* ❌ Function is not serializable */, |
| }) { |
| return ( |
| <div> |
| <button onClick={onClick}>Increment</button> |
| </div> |
| ) |
| } |
| ``` |
|
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| |
|
|
| Combining Server and Client Components allows you to build applications that are both performant and interactive: |
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| 1. **Server Components**: Use for static content, data fetching, and SEO-friendly elements. |
| 2. **Client Components**: Use for interactive elements that require state, effects, or browser APIs. |
| 3. **Component composition**: Nest Client Components within Server Components as needed for a clear separation of server and client logic. |
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| In the following example: |
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| - `Header` is a Server Component handling static content. |
| - `Counter` is a Client Component enabling interactivity within the page. |
|
|
| ```tsx filename="app/page.tsx" highlight={2,8} switcher |
| import Header from './header' |
| import Counter from './counter' |
| |
| export default function Page() { |
| return ( |
| <div> |
| <Header /> |
| <Counter /> |
| </div> |
| ) |
| } |
| ``` |
|
|
| ```jsx filename="app/page.js" highlight={2,8} switcher |
| import Header from './header' |
| import Counter from './counter' |
| |
| export default function Page() { |
| return ( |
| <div> |
| <Header /> |
| <Counter /> |
| </div> |
| ) |
| } |
| ``` |
|
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| |
|
|
| See the [React documentation](https://react.dev/reference/rsc/use-client) for more information on `'use client'`. |
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