Nested layouts in NextJS

Introduction

Nested layouts help organize pages by sharing common parts like headers or sidebars. They make your app easier to build and keep consistent.

You want a main layout with a header and footer shared by many pages.

You have a dashboard section with its own sidebar inside the main layout.

You want to reuse a layout for blog posts that share a style different from the homepage.

You want to keep your code clean by separating page parts into smaller layouts.

Syntax

NextJS

export default function Layout({ children }) {
  return (
    <html>
      <body>
        <header>Header content</header>
        {children}
        <footer>Footer content</footer>
      </body>
    </html>
  )
}

The children prop is where nested pages or layouts appear.

Each layout wraps its nested content, creating a tree of layouts.

Examples

This is the root layout wrapping the whole app.

NextJS

app/layout.js

export default function RootLayout({ children }) {
  return (
    <html>
      <body>
        <header>Main header</header>
        {children}
        <footer>Main footer</footer>
      </body>
    </html>
  )
}

This layout wraps all dashboard pages inside the root layout.

NextJS

app/dashboard/layout.js

export default function DashboardLayout({ children }) {
  return (
    <div>
      <nav>Dashboard sidebar</nav>
      <main>{children}</main>
    </div>
  )
}

This page is shown inside the dashboard layout, which is inside the root layout.

NextJS

app/dashboard/page.js

export default function DashboardPage() {
  return <p>Dashboard home content</p>
}

Sample Program

This example shows a root layout with header and footer. Inside it, the dashboard layout adds a sidebar and main area. The dashboard page content appears inside the dashboard layout.

NextJS

// app/layout.js
export default function RootLayout({ children }) {
  return (
    <html lang="en">
      <body>
        <header style={{ padding: '1rem', backgroundColor: '#eee' }}>
          <h1>My Site</h1>
        </header>
        {children}
        <footer style={{ padding: '1rem', backgroundColor: '#eee' }}>
          <p>© 2024 My Site</p>
        </footer>
      </body>
    </html>
  )
}

// app/dashboard/layout.js
export default function DashboardLayout({ children }) {
  return (
    <div style={{ display: 'flex' }}>
      <nav style={{ width: '200px', backgroundColor: '#ddd', padding: '1rem' }}>
        <ul>
          <li>Dashboard Home</li>
          <li>Settings</li>
        </ul>
      </nav>
      <main style={{ flex: 1, padding: '1rem' }}>{children}</main>
    </div>
  )
}

// app/dashboard/page.js
export default function DashboardPage() {
  return <p>Welcome to your dashboard!</p>
}

Important Notes

Layouts in Next.js 13+ live in the app folder and wrap nested folders/pages automatically.

Use semantic HTML and ARIA roles inside layouts for better accessibility.

Test layouts by viewing nested pages in the browser and using DevTools to inspect structure.

Summary

Nested layouts let you share page parts like headers and sidebars easily.

They keep your app organized and consistent.

Next.js automatically combines layouts from parent folders down to pages.

Practice

1. What is the main purpose of nested layouts in Next.js?

easy

A. To handle user authentication

B. To load data from external APIs

C. To share common UI parts like headers and sidebars across pages

D. To manage server-side rendering only

Solution

1. Step 1: Understand what nested layouts do

   Nested layouts allow you to reuse UI parts like headers and sidebars in multiple pages.

2. Step 2: Compare with other options

   Loading data, authentication, and server-side rendering are separate concerns not handled by nested layouts.

3. Final Answer:

   To share common UI parts like headers and sidebars across pages -> Option C

4. Quick Check:

   Nested layouts = shared UI parts [OK]

Hint: Nested layouts share UI parts like headers [OK]

Common Mistakes:

• Confusing layouts with data fetching
• Thinking layouts handle authentication
• Believing layouts only affect server rendering

2. Which file name is used to define a layout in Next.js 14+ nested layouts system?

easy

A. index.js

B. page.js

C. app.js

D. layout.js

Solution

1. Step 1: Recall Next.js layout file naming

   Layouts are defined in files named layout.js inside folders.

2. Step 2: Differentiate from other files

   page.js defines pages, app.js is not used in App Router, and index.js is a page entry.

3. Final Answer:

   layout.js -> Option D

4. Quick Check:

   Layout file = layout.js [OK]

Hint: Layouts use layout.js files, not page.js [OK]

Common Mistakes:

• Using page.js instead of layout.js for layouts
• Confusing app.js with layout.js
• Thinking index.js defines layouts

3. Given this folder structure and files:

/app/layout.js
  export default function RootLayout({ children }) {
    return {children}
  }

/app/dashboard/layout.js
  export default function DashboardLayout({ children }) {
    return 
{children}
  }

/app/dashboard/page.js
  export default function DashboardPage() {
    return 
Dashboard
  }

What will be the rendered HTML structure when visiting /dashboard?

medium

A. Dashboard

B. Dashboard

C. Dashboard

D. Dashboard

Solution

1. Step 1: Understand layout nesting order

   The root layout wraps the whole app with <html><body>. The dashboard layout wraps the dashboard page inside a <section>.

2. Step 2: Combine layouts and page output

   The final output nests the dashboard page inside <section>, which is inside <body> and <html>.

3. Final Answer:

   <html><body><section><h1>Dashboard</h1></section></body></html> -> Option B

4. Quick Check:

   Layouts wrap children in folder order [OK]

Hint: Layouts wrap children top-down by folder nesting [OK]

Common Mistakes:

• Mixing order of html and section tags
• Placing body inside section incorrectly
• Ignoring root layout wrapping

4. You have this layout file:

export default function Layout({ children }) {
  return 
{children}
}

But your page content does not appear inside the layout when you visit the page. What is the likely cause?

medium

A. The layout file is not named layout.js

B. The layout component must return a fragment, not a div

C. The page file is missing export default

D. The layout component must not accept children

Solution

1. Step 1: Check layout file naming

   Next.js requires the layout file to be named exactly layout.js to apply nested layouts.

2. Step 2: Verify other options

   Returning a div is valid, pages must export default, and layouts must accept children to render nested content.

3. Final Answer:

   The layout file is not named layout.js -> Option A

4. Quick Check:

   Layout file name = layout.js [OK]

Hint: Layout file must be named layout.js exactly [OK]

Common Mistakes:

• Using wrong file name like Layout.js or layout.jsx
• Thinking layout can't use div wrapper
• Forgetting to export default in page

5. You want a nested layout structure where:
- The root layout adds a header
- The dashboard layout adds a sidebar
- The dashboard page shows content

Which code correctly nests these layouts and page in Next.js 14+?

// /app/layout.js
export default function RootLayout({ children }) {
  return 
Header
{children}
}

// /app/dashboard/layout.js
export default function DashboardLayout({ children }) {
  return 
Sidebar
{children}
}

// /app/dashboard/page.js
export default function DashboardPage() {
  return 
Dashboard Content
}

hard

A. The page content will be inside <main> inside <div> with sidebar, wrapped by <body> with header

B. The sidebar will replace the header because layouts cannot nest

C. The header will not show because only one layout is allowed

D. The page will render without sidebar or header because layouts are ignored

Solution

1. Step 1: Understand layout nesting in Next.js

   Layouts nest by folder structure: root layout wraps dashboard layout, which wraps the page.

2. Step 2: Analyze the given code structure

   The root layout adds a header inside . The dashboard layout adds a sidebar inside a div. The page renders main content.

3. Step 3: Combine nesting results

   The final render is
   Header
   Sidebar

   Dashboard Content
   .

4. Final Answer:

   The page content will be inside <main> inside <div> with sidebar, wrapped by <body> with header -> Option A

5. Quick Check:

   Layouts nest by folder, wrapping children [OK]

Hint: Layouts wrap children top-down by folder nesting [OK]

Common Mistakes:

• Thinking layouts replace each other instead of nesting
• Assuming only one layout can be active
• Ignoring children prop in layouts