Layout vs template difference in NextJS - Hands-On Comparison

Understanding Layout vs Template in Next.js

📖 Scenario: You are building a simple website with Next.js. You want to understand how to use layouts and templates to organize your pages. Layouts help you keep common parts like headers and footers consistent. Templates help you create page structures that can change content but keep the same style.

🎯 Goal: Build a Next.js app with a RootLayout that wraps all pages and a DashboardTemplate that structures dashboard pages. See how layouts and templates differ in usage and structure.

📋 What You'll Learn

Create a RootLayout component with a header and footer

Create a DashboardTemplate component with a sidebar and main content area

Use the RootLayout to wrap the entire app

Use the DashboardTemplate inside a dashboard page

💡 Why This Matters

🌍 Real World

Web developers use layouts and templates in Next.js to build websites with consistent structure and reusable page designs.

💼 Career

Understanding layouts and templates is essential for building scalable Next.js applications and working in teams on professional web projects.

1

Create the RootLayout component

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 "Site Header", and a <footer> containing the text "Site Footer". The component should accept a children prop and render it inside the <body> between header and footer.

NextJS

// Create RootLayout component in app/layout.tsx
// Include , ,  with "Site Header",  with "Site Footer"
// Render children between header and footer

Hint

Remember to wrap children between header and footer inside the body tag.

2

Add a configuration variable for sidebar items

Create a file app/dashboard/template.tsx. Inside it, create a constant array called sidebarItems with these exact strings: 'Home', 'Profile', 'Settings'. This will be used to show sidebar links in the dashboard template.

NextJS

// Create sidebarItems array with 'Home', 'Profile', 'Settings'

Hint

Use a constant array with the exact names for sidebar items.

3

Create the DashboardTemplate component using sidebarItems

In app/dashboard/template.tsx, create a React functional component called DashboardTemplate that accepts a children prop. It should render a <div> with two sections: a <nav> listing each item from sidebarItems inside <li> elements within a <ul>, and a <main> that renders the children. Use .map() to create the list items. Make sure to add a key prop to each <li>.

NextJS

export const sidebarItems = ['Home', 'Profile', 'Settings'];

// Create DashboardTemplate component that renders sidebarItems in  and children in 

Hint

Use sidebarItems.map(item => <li key={item}>{item}</li>) to list sidebar items.

4

Use DashboardTemplate inside a dashboard page

Create a file app/dashboard/page.tsx with a React functional component called DashboardPage that is the default export. Inside it, return the DashboardTemplate component wrapping a <p> with the text "Welcome to the dashboard". Import DashboardTemplate from ./template. This shows how templates are used inside pages.

NextJS

// Create DashboardPage component in app/dashboard/page.tsx
// Import DashboardTemplate from './template'
// Use DashboardTemplate to wrap a  with "Welcome to the dashboard"

Hint

Import DashboardTemplate and use it to wrap the paragraph inside DashboardPage.

Practice

1. In Next.js, what is the main role of a layout component?

easy

A. To manage client-side state

B. To provide common page structure like headers and footers

C. To handle API requests

D. To define unique content for each page

Solution

1. Step 1: Understand layout purpose

   Layouts in Next.js wrap pages to provide shared UI elements like headers and footers.

2. Step 2: Differentiate from templates

   Templates hold unique page content, not common structure.

3. Final Answer:

   To provide common page structure like headers and footers -> Option B

4. Quick Check:

   Layout = common structure [OK]

Hint: Layouts wrap pages with shared UI elements [OK]

Common Mistakes:

• Confusing layouts with templates
• Thinking layouts handle data fetching
• Assuming layouts manage state

2. Which of the following is the correct way to define a layout in Next.js 14+ using the App Router?

easy

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

B. function Layout() { return Page Content }

C. const Layout = () => Header

D. export function layout() { return {children} }

Solution

1. Step 1: Check export and props

   Layouts must be default exported and receive children prop to wrap page content.

2. Step 2: Validate syntax

   export default function Layout({ children }) { return
   {children} } correctly exports a function with { children } and returns JSX wrapping children.

3. Final Answer:

   export default function Layout({ children }) { return <div>{children}</div> } -> Option A

4. Quick Check:

   Default export + children prop = export default function Layout({ children }) { return
   {children}
   } [OK]

Hint: Layouts must export default and accept children [OK]

Common Mistakes:

• Not exporting default
• Missing children prop
• Using lowercase function name for layout

3. Given this Next.js layout component:

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

And a page component:

export default function Page() {
  return <main>Welcome!</main>
}

What will be the rendered HTML structure?

medium

A. Site HeaderWelcome!Site Footer

B. Welcome!

C. Site HeaderSite Footer

D. Welcome!

Solution

1. Step 1: Understand layout wrapping

   The layout wraps the page content inside <html> and <body> tags, adding header and footer around children.

2. Step 2: Insert page content

   The page returns <main>Welcome!</main>, which is placed where {children} is in layout.

3. Final Answer:

   <html><body><header>Site Header</header><main>Welcome!</main><footer>Site Footer</footer></body></html> -> Option A

4. Quick Check:

   Layout wraps page content with header/footer [OK]

Hint: Children content appears inside layout's wrapper [OK]

Common Mistakes:

• Ignoring layout wrapping
• Thinking page replaces entire layout
• Missing header or footer in output

4. You wrote this layout in Next.js:

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

But the page content does not render inside the layout. What is the problem?

medium

A. The footer tag is invalid in layouts

B. The layout should not have a header

C. The layout function does not accept the children prop

D. The layout must be a class component

Solution

1. Step 1: Check function parameters

   The layout must accept { children } as a parameter to render page content inside.

2. Step 2: Identify missing children prop

   The code misses { children } in the function signature, so it cannot render page content.

3. Final Answer:

   The layout function does not accept the children prop -> Option C

4. Quick Check:

   Missing children prop causes no page content [OK]

Hint: Layouts must accept children prop to render page content [OK]

Common Mistakes:

• Forgetting to add children parameter
• Thinking header/footer cause error
• Believing layouts must be class components

5. You want to create a Next.js page that uses a layout with a sidebar and header. The sidebar should only appear on some pages, but the header should always be present. How should you organize layouts and templates to achieve this?

hard

A. Add sidebar inside each page component instead of layouts

B. Put header and sidebar in the same layout used by all pages

C. Use templates only and avoid layouts for shared UI

D. Create a main layout with header, then nested layouts for pages with sidebar

Solution

1. Step 1: Identify shared and conditional UI

   The header is shared by all pages, so it belongs in the main layout. Sidebar is conditional, so it fits in nested layouts.

2. Step 2: Use nested layouts

   Create a main layout with header, then nest layouts for pages needing sidebar to add it without affecting others.

3. Final Answer:

   Create a main layout with header, then nested layouts for pages with sidebar -> Option D

4. Quick Check:

   Nested layouts handle conditional UI [OK]

Hint: Use nested layouts for conditional UI parts [OK]

Common Mistakes:

• Putting all UI in one layout causing unwanted sidebar
• Adding sidebar directly in pages losing layout benefits
• Avoiding layouts and mixing shared UI in templates