layout.js

The layout file is used to define a layout in your Next.js application.

export default function DashboardLayout({
  children,
}: {
  children: React.ReactNode
}) {
  return <section>{children}</section>
}

A root layout is the top-most layout in the root app directory. It is used to define the <html> and <body> tags and other globally shared UI.

export default function RootLayout({
  children,
}: {
  children: React.ReactNode
}) {
  return (
    <html lang="en">
      <body>{children}</body>
    </html>
  )
}

Layout components should accept and use a children prop. During rendering, children will be populated with the route segments the layout is wrapping. These will primarily be the component of a child Layout (if it exists) or Page, but could also be other special files like Loading or Error when applicable.

`params` (optional)

A promise that resolves to an object containing the dynamic route parameters object from the root segment down to that layout.

export default async function Layout({
  params,
}: {
  params: Promise<{ team: string }>
}) {
  const { team } = await params
}

Example Route	URL	`params`
`app/dashboard/[team]/layout.js`	`/dashboard/1`	`Promise<{ team: '1' }>`
`app/shop/[tag]/[item]/layout.js`	`/shop/1/2`	`Promise<{ tag: '1', item: '2' }>`
`app/blog/[...slug]/layout.js`	`/blog/1/2`	`Promise<{ slug: ['1', '2'] }>`

Since the params prop is a promise. You must use async/await or React's use function to access the values.
- In version 14 and earlier, params was a synchronous prop. To help with backwards compatibility, you can still access it synchronously in Next.js 15, but this behavior will be deprecated in the future.

Root Layout

The app directory must include a root app/layout.js.

export default function RootLayout({
  children,
}: {
  children: React.ReactNode
}) {
  return (
    <html>
      <body>{children}</body>
    </html>
  )
}

The root layout must define <html> and <body> tags.
- You should not manually add <head> tags such as <title> and <meta> to root layouts. Instead, you should use the Metadata API which automatically handles advanced requirements such as streaming and de-duplicating <head> elements.
You can use route groups to create multiple root layouts.
- Navigating across multiple root layouts will cause a full page load (as opposed to a client-side navigation). For example, navigating from /cart that uses app/(shop)/layout.js to /blog that uses app/(marketing)/layout.js will cause a full page load. This only applies to multiple root layouts.

Caveats

Request Object

Layouts are cached in the client during navigation to avoid unnecessary server requests.

Layouts do not rerender. They can be cached and reused to avoid unnecessary computation when navigating between pages. By restricting layouts from accessing the raw request, Next.js can prevent the execution of potentially slow or expensive user code within the layout, which could negatively impact performance.

To access the request object, you can use headers and cookies APIs in Server Components and Functions.

import { cookies } from 'next/headers'

export default async function Layout({ children }) {
  const cookieStore = await cookies()
  const theme = cookieStore.get('theme')
  return '...'
}

Query params

Layouts do not rerender on navigation, so they cannot access search params which would otherwise become stale.

To access updated query parameters, you can use the Page searchParams prop, or read them inside a Client Component using the useSearchParams hook. Since Client Components re-render on navigation, they have access to the latest query parameters.

'use client'

import { useSearchParams } from 'next/navigation'

export default function Search() {
  const searchParams = useSearchParams()

  const search = searchParams.get('search')

  return '...'
}

Pathname

Layouts do not re-render on navigation, so they do not access pathname which would otherwise become stale.

To access the current pathname, you can read it inside a Client Component using the usePathname hook. Since Client Components re-render during navigation, they have access to the latest pathname.

'use client'

import { usePathname } from 'next/navigation'

// Simplified breadcrumbs logic
export default function Breadcrumbs() {
  const pathname = usePathname()
  const segments = pathname.split('/')

  return (
    <nav>
      {segments.map((segment, index) => (
        <span key={index}>
          {' > '}
          {segment}
        </span>
      ))}
    </nav>
  )
}

Fetching Data

Layouts cannot pass data to their children. However, you can fetch the same data in a route more than once, and use React cache to dedupe the requests without affecting performance.

Alternatively, when using fetchin Next.js, requests are automatically deduped.

export async function getUser(id: string) {
  const res = await fetch(`https://.../users/${id}`)
  return res.json()
}

Accessing child segments

Layouts do not have access to the route segments below itself. To access all route segments, you can use useSelectedLayoutSegment or useSelectedLayoutSegments in a Client Component.

'use client'

import Link from 'next/link'
import { useSelectedLayoutSegment } from 'next/navigation'

export default function NavLink({
  slug,
  children,
}: {
  slug: string
  children: React.ReactNode
}) {
  const segment = useSelectedLayoutSegment()
  const isActive = slug === segment

  return (
    <Link
      href={`/blog/${slug}`}
      // Change style depending on whether the link is active
      style={{ fontWeight: isActive ? 'bold' : 'normal' }}
    >
      {children}
    </Link>
  )
}

Examples

Metadata

You can modify the <head> HTML elements such as title and meta using the metadata object or generateMetadata function.

import type { Metadata } from 'next'

export const metadata: Metadata = {
  title: 'Next.js',
}

export default function Layout({ children }: { children: React.ReactNode }) {
  return '...'
}

Good to know: You should not manually add <head> tags such as <title> and <meta> to root layouts. Instead, use the Metadata APIs which automatically handles advanced requirements such as streaming and de-duplicating <head> elements.

Active Nav Links

You can use the usePathname hook to determine if a nav link is active.

Since usePathname is a client hook, you need to extract the nav links into a Client Component, which can be imported into your layout:

'use client'

import { usePathname } from 'next/navigation'
import Link from 'next/link'

export function NavLinks() {
  const pathname = usePathname()

  return (
    <nav>
      <Link className={`link ${pathname === '/' ? 'active' : ''}`} href="/">
        Home
      </Link>

      <Link
        className={`link ${pathname === '/about' ? 'active' : ''}`}
        href="/about"
      >
        About
      </Link>
    </nav>
  )
}

Displaying content based on `params`

Using dynamic route segments, you can display or fetch specific content based on the params prop.

export default async function DashboardLayout({
  children,
  params,
}: {
  children: React.ReactNode
  params: Promise<{ team: string }>
}) {
  const { team } = await params

  return (
    <section>
      <header>
        <h1>Welcome to {team}'s Dashboard</h1>
      </header>
      <main>{children}</main>
    </section>
  )
}

Reading `params` in Client Components

To use params in a Client Component (which cannot be async), you can use React's use function to read the promise:

'use client'

import { use } from 'react'

export default function Page({
  params,
}: {
  params: Promise<{ slug: string }>
}) {
  const { slug } = use(params)
}

Version History

Version	Changes
`v15.0.0-RC`	`params` is now a promise. A codemod is available.
`v13.0.0`	`layout` introduced.

Reference

Props

`children` (required)