Metadata in layouts in NextJS - Mini Project: Build & Apply

Metadata in layouts

📖 Scenario: You are building a simple Next.js website with a consistent layout. You want to add metadata like the page title and description that applies to all pages using a layout component.

🎯 Goal: Create a Next.js layout component that defines metadata for the entire site using the metadata export. This metadata should include a title and description. Then use this layout in your app.

📋 What You'll Learn

Create a layout component file named layout.js in the app directory

Add a metadata export object with title and description properties

Use the children prop to render nested page content inside the layout

Export the layout component as default

💡 Why This Matters

🌍 Real World

Websites often need consistent metadata for SEO and social sharing. Using layouts to define metadata helps keep it organized and reusable.

💼 Career

Understanding Next.js layouts and metadata is important for frontend developers working on modern React-based web applications.

1

Create the layout component file

Create a file named layout.js inside the app directory. Inside it, define a React functional component named RootLayout that accepts a children prop and returns a html element with a body containing the children. Export this component as default.

NextJS

export default function RootLayout({ children }) {
  // Your code here
}

Hint

Remember to wrap the children inside <html> and <body> tags and set the language attribute.

2

Add metadata export with title and description

In the layout.js file, add an exported constant named metadata that is an object with two properties: title set to 'My Next.js Site' and description set to 'A simple Next.js app with metadata in layout.'.

NextJS

export const metadata = {
  // Your code here
}

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

Hint

Use export const metadata = { title: '...', description: '...' } syntax at the top of the file.

3

Use the layout in the app directory

Ensure the layout.js file is inside the app directory so Next.js uses it as the root layout for all pages. Confirm the file exports the RootLayout component as default and the metadata object is exported.

NextJS

// Confirm the file is named layout.js inside app directory
// Confirm exports are correct
// Your code here

Hint

Make sure the file is named exactly layout.js inside the app folder and exports both metadata and RootLayout.

4

Add a simple page to test the layout

Create a file named page.js inside the app directory. Export a default React functional component named HomePage that returns a <main> element with the text 'Welcome to My Next.js Site'. This page will use the layout and metadata you created.

NextJS

// Create page.js inside app directory
// Export default function HomePage returning Welcome to My Next.js Site
// Your code here

Hint

Remember to export the page component as default and return the <main> element with the exact text.

Practice

1. What is the main purpose of the metadata object in a Next.js layout?

easy

A. To manage client-side state in the layout

B. To style the layout components with CSS

C. To define page information like title and description for browsers and search engines

D. To handle user authentication in the layout

Solution

1. Step 1: Understand the role of metadata in Next.js

   The metadata object is used to provide page details such as title and description that browsers and search engines use.

2. Step 2: Differentiate metadata from other layout tasks

   Styling, authentication, and state management are handled separately, not by metadata.

3. Final Answer:

   To define page information like title and description for browsers and search engines -> Option C

4. Quick Check:

   Metadata = page info for browsers and SEO [OK]

Hint: Metadata sets page info, not styles or logic [OK]

Common Mistakes:

• Confusing metadata with CSS styling
• Thinking metadata manages user data
• Assuming metadata controls client state

2. Which of the following is the correct way to export metadata in a Next.js layout file?

easy

A. export metadata = { title: 'Home' };

B. const metadata = { title: 'Home' }; export default metadata;

C. export function metadata() { return { title: 'Home' }; }

D. export const metadata = { title: 'Home' };

Solution

1. Step 1: Recall Next.js metadata export syntax

   Next.js expects a named export called metadata as a constant object.

2. Step 2: Check each option's syntax

   export const metadata = { title: 'Home' }; correctly exports a constant object. const metadata = { title: 'Home' }; export default metadata; exports default, which is incorrect. export function metadata() { return { title: 'Home' }; } exports a function, not an object. export metadata = { title: 'Home' }; has invalid export syntax.

3. Final Answer:

   export const metadata = { title: 'Home' }; -> Option D

4. Quick Check:

   Named const export = correct syntax [OK]

Hint: Use named const export for metadata object [OK]

Common Mistakes:

• Using default export instead of named export
• Exporting a function instead of an object
• Incorrect export syntax without const

3. Given this layout file snippet, what will be the page title shown in the browser tab?

export const metadata = { title: 'Dashboard' };

export default function Layout({ children }) {
  return <main>{children}</main>;
}

medium

A. Dashboard

B. Home

C. Layout

D. No title will be shown

Solution

1. Step 1: Identify the metadata title value

   The metadata object sets title to 'Dashboard'.

2. Step 2: Understand Next.js behavior with metadata

   Next.js uses this metadata to set the HTML <title> tag, which appears in the browser tab.

3. Final Answer:

   Dashboard -> Option A

4. Quick Check:

   metadata.title = browser tab title [OK]

Hint: metadata.title sets browser tab title [OK]

Common Mistakes:

• Assuming default title if metadata is present
• Confusing layout function name with title
• Thinking children content affects title

4. You wrote this layout metadata but the page title does not update:

const metadata = { title: 'Profile' };

export default function Layout({ children }) {
  return <main>{children}</main>;
}

What is the error?

medium

A. The title property must be inside a function

B. metadata must be exported with export const metadata

C. Layout must be a class component to use metadata

D. Children must be wrapped in a <section> tag

Solution

1. Step 1: Check metadata export

   The metadata object is declared but not exported, so Next.js cannot read it.

2. Step 2: Confirm correct export syntax

   Next.js requires export const metadata = { ... } to recognize metadata.

3. Final Answer:

   metadata must be exported with export const metadata -> Option B

4. Quick Check:

   Export metadata for Next.js to use it [OK]

Hint: Always export metadata as named const [OK]

Common Mistakes:

• Forgetting to export metadata
• Using function or class for metadata
• Changing children wrapper tags unnecessarily

5. You want to set a default description for all pages using a root layout metadata, but override it on a specific page. How should you structure your Next.js metadata exports?

hard

A. Export metadata with description in root layout, then export metadata with a different description in the page layout

B. Only export metadata in the root layout; page metadata is ignored

C. Merge metadata objects manually inside the root layout component

D. Use a global CSS file to set description meta tag

Solution

1. Step 1: Understand metadata inheritance in Next.js

   Metadata in layouts is merged, so root layout metadata applies by default.

2. Step 2: Override metadata in nested layouts or pages

   Exporting metadata in a page or nested layout overrides root metadata for that page.

3. Step 3: Confirm correct approach

   Export metadata with description in root layout, then export metadata with a different description in the page layout correctly describes exporting metadata in root and overriding in page layout.

4. Final Answer:

   Export metadata with description in root layout, then export metadata with a different description in the page layout -> Option A

5. Quick Check:

   Root metadata sets default, page metadata overrides [OK]

Hint: Root metadata sets default; page metadata overrides [OK]

Common Mistakes:

• Assuming page metadata is ignored if root exists
• Trying to merge metadata manually in code
• Using CSS to set metadata tags