Parallel routes concept in NextJS - Mini Project: Build & Apply

Building Parallel Routes in Next.js

📖 Scenario: You are creating a simple Next.js app that shows two different sections side by side: a Profile and a Settings panel. Both should be visible at the same time using parallel routes.

🎯 Goal: Build a Next.js app with parallel routes to display profile and settings components side by side on the same page.

📋 What You'll Learn

Create a main layout with two parallel route outlets named profile and settings

Create a profile route that shows user profile information

Create a settings route that shows user settings options

Use Next.js App Router conventions with layout.js and page.js files

Ensure the parallel routes render side by side in a responsive layout

💡 Why This Matters

🌍 Real World

Parallel routes let you show multiple views or panels at once, like a dashboard with different widgets visible side by side.

💼 Career

Understanding parallel routes is useful for building complex user interfaces in Next.js apps, a common skill for frontend developers.

1

Set up the main layout with parallel route slots

Create a layout.js file inside the app directory. Inside it, create a React component that returns a div with two section elements. Each section should render a Slot component with names profile and settings respectively. Import Slot from next/navigation.

NextJS

import { Slot } from 'next/navigation'

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

Hint

Remember to import Slot from next/navigation and use it with the name prop for parallel routes.

2

Create the profile parallel route page

Inside the app directory, create a folder named @profile. Inside it, create a page.js file. Export a React component that returns a div with the text User Profile Section.

NextJS

import React from 'react'

export default function ProfilePage() {
  // Your code here
}

Hint

Create a simple React component that returns a div with the exact text User Profile Section.

3

Create the settings parallel route page

Inside the app directory, create a folder named @settings. Inside it, create a page.js file. Export a React component that returns a div with the text User Settings Section.

NextJS

import React from 'react'

export default function SettingsPage() {
  // Your code here
}

Hint

Create a React component that returns a div with the exact text User Settings Section.

4

Add the main page to render both parallel routes

Inside the app directory, create a page.js file. Export a React component that returns a div with the text Main Dashboard. This page will render alongside the parallel routes defined in the layout.

NextJS

export default function Page() {
  // Your code here
}

Hint

Create a simple React component that returns a div with the text Main Dashboard.

Practice

1. What is the main purpose of parallel routes in Next.js?

easy

A. To disable navigation between pages

B. To load pages sequentially one after another

C. To replace client-side routing with server-side only

D. To display multiple parts of a page simultaneously

Solution

1. Step 1: Understand what parallel routes do

   Parallel routes allow showing multiple UI sections at the same time on a page.

2. Step 2: Compare options with this understanding

   Only To display multiple parts of a page simultaneously correctly describes this purpose; others describe unrelated behaviors.

3. Final Answer:

   To display multiple parts of a page simultaneously -> Option D

4. Quick Check:

   Parallel routes = show multiple parts [OK]

Hint: Parallel routes show multiple page parts at once [OK]

Common Mistakes:

• Thinking parallel routes load pages one after another
• Confusing parallel routes with disabling navigation
• Assuming parallel routes replace client-side routing

2. Which folder naming pattern is used to define a parallel route in Next.js?

easy

A. Using parentheses like (route)

B. Using square brackets like [route]

C. Using curly braces like {route}

D. Using angle brackets like <route>

Solution

1. Step 1: Recall folder naming for parallel routes

   Next.js uses parentheses around folder names to mark parallel routes.

2. Step 2: Match options to this rule

   Only Using parentheses like (route) uses parentheses, which is correct for parallel routes.

3. Final Answer:

   Using parentheses like (route) -> Option A

4. Quick Check:

   Parallel routes folder = parentheses [OK]

Hint: Parallel routes folders use parentheses ( ) [OK]

Common Mistakes:

• Using square brackets which are for dynamic routes
• Confusing with curly braces or angle brackets
• Not using any special characters for parallel routes

3. Given this folder structure in Next.js:

app/
  (sidebar)/
    page.jsx
  (content)/
    page.jsx
  layout.jsx

What will happen when the app renders layout.jsx with parallel routes?

medium

A. Both sidebar and content pages render side by side inside layout

B. Only the sidebar page renders, content is ignored

C. Only the content page renders, sidebar is ignored

D. Neither sidebar nor content pages render automatically

Solution

1. Step 1: Understand parallel routes folder names

   Folders named with parentheses define parallel routes that render simultaneously.

2. Step 2: Apply to given structure

   Both (sidebar) and (content) are parallel routes, so their pages render side by side inside layout.

3. Final Answer:

   Both sidebar and content pages render side by side inside layout -> Option A

4. Quick Check:

   Parallel routes render all named folders simultaneously [OK]

Hint: Parentheses folders render together inside layout [OK]

Common Mistakes:

• Thinking only one parallel route renders at a time
• Assuming parallel routes need manual import to render
• Confusing parallel routes with nested routes

4. You have this code in your layout.jsx to render parallel routes:

import { Slot } from 'next/navigation';

export default function Layout() {
  return (
    

      <Slot name="sidebar" />
      <Slot name="content" />
    
  );
}

Why does this code cause an error?

medium

A. Because Slot must be imported from 'next/navigation' as a named import

B. Because <Slot /> should be self-closing JSX tags, not string literals

C. Because parallel routes cannot use Slot components

D. Because Slot requires a default export, not named

Solution

1. Step 1: Check JSX syntax in return statement

   The code uses <Slot name="sidebar" /> as a string literal, not as JSX tags.

2. Step 2: Correct JSX usage

   It should be <Slot name="sidebar" /> without quotes, as a self-closing JSX component.

3. Final Answer:

   Because <Slot /> should be self-closing JSX tags, not string literals -> Option B

4. Quick Check:

   JSX tags must not be strings [OK]

Hint: Use JSX tags, not strings, for [OK]

Common Mistakes:

• Writing JSX tags as strings inside return
• Importing Slot incorrectly
• Thinking Slot can't be used in parallel routes

5. You want to create a page with a sidebar and main content using parallel routes. Which folder structure and code snippet correctly implements this in Next.js?

app/
  (sidebar)/
    page.jsx
  (main)/
    page.jsx
  layout.jsx

And in layout.jsx:

export default function Layout() {
  return (
    

      {/* What goes here? */}
    
  );
}

hard

A. <Slot />

B. <Slot name="content" />
<Slot name="sidebar" />

C. <Slot name="sidebar" />
<Slot name="main" />

D. <Outlet name="sidebar" />
<Outlet name="main" />

Solution

1. Step 1: Match folder names to Slot names

   Folders are named (sidebar) and (main), so Slots must use these exact names.

2. Step 2: Check code snippet for correct Slot usage

   <Slot name="sidebar" /> <Slot name="main" /> uses <Slot name="sidebar" /> and <Slot name="main" />, matching folder names and correct JSX syntax.

3. Final Answer:

   <Slot name="sidebar" /> <Slot name="main" /> -> Option C

4. Quick Check:

   Slot names = folder names [OK]

Hint: Slot names must match parallel route folder names [OK]

Common Mistakes:

• Using wrong Slot names that don't match folders
• Using instead of
• Using only one Slot for multiple parallel routes