Intercepting routes (.) in NextJS - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to create an intercepting route segment in Next.js.

NextJS

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

export default function DashboardLayout({ children }) {
  return <section>{children}</section>;
}

// To intercept routes, use the [1] folder inside app directory.

Drag options to blanks, or click blank then click option'

Aintercept

Bgroup

Cparallel

Dsegment

Attempts:

3 left

💡 Hint

Common Mistakes

Using 'intercept' folder which does not exist.

Using 'segment' which is a general term but not a folder name.

Using 'parallel' which is unrelated here.

In Next.js, to intercept routes without affecting the URL, you use a group folder named (.).

2fill in blank

medium

Complete the code to define an intercepting route segment that renders a sidebar.

NextJS

export default function Layout({ children }) {
  return (
    <div>
      <aside>[1]</aside>
      <main>{children}</main>
    </div>
  );
}

Drag options to blanks, or click blank then click option'

A<Sidebar />

B<Header />

C<Footer />

D<Content />

Attempts:

3 left

💡 Hint

Common Mistakes

Putting

inside

which is semantically incorrect.

Using

or which do not represent sidebar.

The sidebar component is rendered inside the

element to show navigation or extra info.

3fill in blank

hard

Fix the error in the intercepting route segment to correctly render the children.

NextJS

export default function Layout({ children }) {
  return (
    <div>
      <nav>Menu</nav>
      [1]
    </div>
  );
}

Drag options to blanks, or click blank then click option'

A{children}

B<Children />

C<children />

Dchildren

Attempts:

3 left

💡 Hint

Common Mistakes

Using which treats children as a component but it's a prop.

Using which is incorrect capitalization and component usage.

Using just 'children' without braces which will not render.

In React and Next.js, to render children passed as props, you use curly braces {children} without angle brackets.

4fill in blank

hard

Fill both blanks to create a parallel route segment that intercepts the main route and renders a modal.

NextJS

export default function ModalLayout({ children, modal }) {
  return (
    <>
      [1]
      <div className="modal">[2]</div>
    </>
  );
}

Drag options to blanks, or click blank then click option'

A<main>{children}</main>

B{children}

C<main />

D{modal}

Attempts:

3 left

💡 Hint

Common Mistakes

Using

which renders an empty main element.

Using {children} without wrapping in

for main content.

Putting {children} inside the modal div instead of the main content.

The main content (default slot) is wrapped in

{children}

and the modal slot is rendered inside the modal div using {modal}.

5fill in blank

hard

Fill all three blanks to create an intercepting route that uses a group folder, renders a header, and shows children content.

NextJS

export default function GroupLayout({ children }) {
  return (
    <div>
      <header>[2]</header>
      <main>[3]</main>
    </div>
  );
}

// The folder name for this layout is [1]

Drag options to blanks, or click blank then click option'

A<Header />

B{children}

C(.)

D<Content />

Attempts:

3 left

💡 Hint

Common Mistakes

Confusing the folder name with component names.

Rendering children inside header instead of main.

Using instead of {children}.

The folder name for this layout is (.), the header component

is rendered inside

, and children are rendered inside

using {children}.

Practice

1. What is the main purpose of intercepting routes in Next.js App Router?

easy

A. To force server-side rendering on every route

B. To reload the entire page on every navigation

C. To disable client-side navigation

D. To add UI parts without leaving the current page

Solution

1. Step 1: Understand intercepting routes concept

   Intercepting routes allow adding UI parts while staying on the same page, avoiding full reloads.

2. Step 2: Compare options with concept

   Options suggesting page reloads, disabling navigation, or forcing server-side rendering contradict the idea of smooth UI updates without full reloads.

3. Final Answer:

   To add UI parts without leaving the current page -> Option D

4. Quick Check:

   Intercepting routes = add UI parts without leaving page [OK]

Hint: Intercepting routes keep you on the page while adding UI [OK]

Common Mistakes:

• Thinking intercepting routes reload the whole page
• Confusing intercepting routes with disabling navigation
• Assuming intercepting routes force server rendering

2. Which folder name syntax is used to create an intercepting route in Next.js App Router?

easy

A. @modal

B. modal

C. (modal)

D. [modal]

Solution

1. Step 1: Recall folder naming for intercepting routes

   Intercepting routes use parentheses around folder names, like (modal), to mark them as intercepting.

2. Step 2: Evaluate options

   (modal) uses parentheses correctly. @modal uses @ for parallel routes, modal omits parentheses for regular routes, and [modal] uses square brackets for dynamic routes.

3. Final Answer:

   (modal) -> Option C

4. Quick Check:

   Intercepting route folder = parentheses [OK]

Hint: Intercepting routes use (folderName) syntax [OK]

Common Mistakes:

• Using square brackets instead of parentheses
• Omitting parentheses for intercepting routes
• Confusing @ folders with intercepting route folders

3. Given this folder structure in Next.js App Router:
app/(modal)/page.tsx
What happens when you navigate to a route inside (modal)?

medium

A. The modal UI appears without leaving the current page

B. The entire page reloads and shows only the modal content

C. Navigation fails with a 404 error

D. The modal opens in a new browser tab

Solution

1. Step 1: Understand intercepting route behavior

   Routes inside (modal) folders add UI parts like modals without leaving the current page.

2. Step 2: Analyze navigation effect

   Navigation triggers modal UI overlay, not a full page reload or error.

3. Final Answer:

   The modal UI appears without leaving the current page -> Option A

4. Quick Check:

   Navigation in (modal) = modal UI without reload [OK]

Hint: Routes in (modal) show UI without page reload [OK]

Common Mistakes:

• Expecting full page reload on modal route
• Thinking navigation causes errors
• Assuming modal opens in new tab

4. You wrote this intercepting route folder: app/@(sidebar)/page.tsx. Why does it cause a build error?

medium

A. Parentheses cannot be combined with @ in folder names

B. The folder name must be all lowercase

C. You need to add a layout.tsx file inside the folder

D. The file extension should be .jsx, not .tsx

Solution

1. Step 1: Check folder naming rules for intercepting routes

   Parentheses indicate intercepting routes; @ folders are separate special folders. Combining them is invalid syntax.

2. Step 2: Identify cause of build error

   Using @(sidebar) mixes two folder naming conventions, causing build failure.

3. Final Answer:

   Parentheses cannot be combined with @ in folder names -> Option A

4. Quick Check:

   Invalid folder name combining ( ) and @ causes error [OK]

Hint: Don't mix ( ) and @ in folder names [OK]

Common Mistakes:

• Thinking lowercase folder name fixes error
• Assuming missing layout.tsx causes build error
• Confusing file extension with folder naming

5. You want to show a sidebar UI on some pages without leaving the current page. Which folder structure correctly implements this intercepting route in Next.js App Router?

hard

A. app/(sidebar)/page.tsx without layout.tsx

B. app/(sidebar)/page.tsx with a layout.tsx inside (sidebar) wrapping children

C. app/@sidebar/page.tsx with page.tsx only

D. app/sidebar/page.tsx with a layout.tsx inside sidebar wrapping children

Solution

1. Step 1: Identify correct intercepting route folder

   Using parentheses (sidebar) marks it as an intercepting route folder.

2. Step 2: Confirm layout usage for UI wrapping

   Adding layout.tsx inside (sidebar) allows wrapping children with sidebar UI, enabling partial UI updates.

3. Step 3: Evaluate other options

   app/sidebar/page.tsx with a layout.tsx inside sidebar wrapping children lacks parentheses, so it's a normal route. app/@sidebar/page.tsx with page.tsx only uses @ which is for special folders, not intercepting routes. app/(sidebar)/page.tsx without layout.tsx misses layout.tsx, so sidebar UI won't wrap children properly.

4. Final Answer:

   app/(sidebar)/page.tsx with a layout.tsx inside (sidebar) wrapping children -> Option B

5. Quick Check:

   Intercepting route with layout wraps UI correctly [OK]

Hint: Use (folder) plus layout.tsx to wrap UI in intercepting routes [OK]

Common Mistakes:

• Omitting layout.tsx inside intercepting route folder
• Using normal folder instead of (folder) for intercepting route
• Confusing @ folders with intercepting route folders