Nested layouts in NextJS - Mini Project: Build & Apply

Nested layouts

📖 Scenario: You are building a simple website with a main layout and a nested dashboard layout inside it. The main layout has a header and footer. The dashboard layout adds a sidebar. You want to organize your pages so that the dashboard pages use both layouts automatically.

🎯 Goal: Create nested layouts in Next.js using the App Router. The main layout wraps all pages with a header and footer. The dashboard layout wraps dashboard pages with a sidebar inside the main layout.

📋 What You'll Learn

Create a main layout component with a header and footer

Create a dashboard layout component with a sidebar

Nest the dashboard layout inside the main layout

Create a dashboard page that uses the nested layouts

💡 Why This Matters

🌍 Real World

Nested layouts help organize complex websites by reusing common page parts like headers, footers, and sidebars.

💼 Career

Understanding nested layouts is important for building scalable React and Next.js applications used in professional web development.

1

Create the main layout

Create a file app/layout.tsx with a React functional component called RootLayout. It should return an HTML structure with <html>, <body>, a <header> containing the text "Main Header", and a <footer> containing the text "Main Footer". Use children as a prop to render nested content inside the <body> between the header and footer.

NextJS

// Your code here

Hint

Remember to create a React functional component named RootLayout that returns the HTML structure with header, children, and footer.

2

Create the dashboard layout

Inside the app/dashboard folder, create a file layout.tsx with a React functional component called DashboardLayout. It should accept children as a prop and return a <div> with a <nav> containing the text "Sidebar" and a <main> containing the children. This layout will be nested inside the main layout.

NextJS

import React from 'react';

// Your code here

Hint

Create a React functional component named DashboardLayout that returns a div with a nav and main containing children.

3

Create a dashboard page

Inside the app/dashboard folder, create a file page.tsx with a React functional component called DashboardPage. It should return a <section> with the text "Welcome to the Dashboard".

NextJS

// Your code here

Hint

Create a React functional component named DashboardPage that returns a section with the welcome text.

4

Complete nested layout usage

Verify that the DashboardPage is wrapped by DashboardLayout, which is nested inside the RootLayout. This happens automatically in Next.js App Router by placing layout.tsx files in app and app/dashboard. No extra code is needed here. Just ensure the files are correctly placed and exported.

NextJS

// No code needed here, just verify file structure and exports

Hint

Make sure all three components are exported correctly and placed in the right folders for Next.js to nest layouts automatically.

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