When to keep components on server in NextJS - Mini Project: Build & Apply

When to Keep Components on Server in Next.js

📖 Scenario: You are building a simple blog homepage using Next.js. You want to decide which parts of the page should be rendered on the server and which parts should be rendered on the client.This helps your page load faster and keeps user interactions smooth.

🎯 Goal: Create a Next.js app with a server component that fetches and displays blog posts, and a client component that handles a like button interaction.

📋 What You'll Learn

Create a server component that fetches blog post data

Create a client component for a like button with interactive state

Use the use client directive for the client component

Compose the client component inside the server component

💡 Why This Matters

🌍 Real World

Many websites use server components to render static content fast and client components for user interactions like buttons and forms.

💼 Career

Understanding when to keep components on the server or client is key for building efficient, scalable Next.js applications in professional web development.

1

Create the blog posts data array

Create a constant called posts that is an array of objects. Each object should have id and title properties with these exact values: { id: 1, title: 'Hello Next.js' } and { id: 2, title: 'Server Components' }.

NextJS

// Create the posts array with two objects
// Your code here

Hint

Use const posts = [ ... ] with two objects inside.

2

Create a client component for the like button

Create a new React component called LikeButton that uses the use client directive at the top. Inside, use useState to track a liked boolean starting as false. Render a button that toggles liked when clicked and shows 'Like' or 'Unlike' accordingly.

NextJS

const posts = [
  { id: 1, title: 'Hello Next.js' },
  { id: 2, title: 'Server Components' }
];

// Create LikeButton client component below
// Your code here

Hint

Remember to add 'use client'; at the top and import useState.

3

Create the server component to display posts

Create a default exported React component called BlogPage that renders a <main> element. Inside, map over the posts array and render each post's title inside an <h2> with a key of post.id. Below the list, include the <LikeButton /> component.

NextJS

'use client';

import { useState } from 'react';

const posts = [
  { id: 1, title: 'Hello Next.js' },
  { id: 2, title: 'Server Components' }
];

export function LikeButton() {
  const [liked, setLiked] = useState(false);
  return (
     setLiked(!liked)} aria-pressed={liked}>
      {liked ? 'Unlike' : 'Like'}
    
  );
}

// Create BlogPage server component below
// Your code here

Hint

Use posts.map(post => <h2 key={post.id}>{post.title}</h2>) inside <main>.

4

Add accessibility and export the components properly

Ensure the LikeButton component has an aria-pressed attribute on the button for accessibility. Confirm that LikeButton is exported as a named export and BlogPage is the default export.

NextJS

'use client';

import { useState } from 'react';

const posts = [
  { id: 1, title: 'Hello Next.js' },
  { id: 2, title: 'Server Components' }
];

export function LikeButton() {
  const [liked, setLiked] = useState(false);
  return (
     setLiked(!liked)} aria-pressed={liked}>
      {liked ? 'Unlike' : 'Like'}
    
  );
}

export default function BlogPage() {
  return (
    
      {posts.map(post => (
        {post.title}
      ))}
      
    
  );
}

// Check accessibility and exports
// Your code here

Hint

Make sure aria-pressed is on the button and exports are correct.

Practice

1. Which of the following is the best reason to keep a component as a server component in Next.js?

easy

A. It requires frequent updates based on user interaction.

B. It needs to handle user clicks and input events.

C. It fetches data securely and renders static content.

D. It uses browser-only APIs like localStorage.

Solution

1. Step 1: Understand server component purpose

   Server components run on the server and are ideal for static content and secure data fetching.

2. Step 2: Identify interactive needs

   Components that handle user clicks or browser APIs must be client components, not server components.

3. Final Answer:

   It fetches data securely and renders static content. -> Option C

4. Quick Check:

   Server components = static + secure data [OK]

Hint: Server components = static or secure data only [OK]

Common Mistakes:

• Choosing server component for interactive UI
• Using browser APIs in server components
• Thinking server components handle events

2. Which syntax correctly forces static rendering for a server component in Next.js 14+?

easy

A. export const dynamic = 'force-static';

B. export const runtime = 'edge';

C. export const dynamic = 'force-dynamic';

D. export const client = true;

Solution

1. Step 1: Recall server component syntax

   Server components can be forced static with export const dynamic = 'force-static';.

2. Step 2: Differentiate other options

   export const dynamic = 'force-dynamic'; (dynamic = 'force-dynamic') forces dynamic rendering, B (runtime = 'edge') sets edge runtime without forcing static, D is invalid syntax.

3. Final Answer:

   export const dynamic = 'force-static'; -> Option A

4. Quick Check:

   Force static = server component [OK]

Hint: Use 'force-static' to keep component server-only [OK]

Common Mistakes:

• Confusing client directive with server component
• Using 'force-dynamic' for server-only components
• Mixing runtime and dynamic exports

3. Consider this Next.js server component code snippet:

export default function Greeting() {
  const name = fetchNameFromDB();
  return <h1>Hello, {name}!</h1>;
}

What will be the output rendered in the browser?

medium

A. <h1>Hello, [name from DB]!</h1>

B. Error: fetchNameFromDB is not defined

C. <h1>Hello, undefined!</h1>

D. Nothing renders because server components cannot fetch data

Solution

1. Step 1: Understand server component data fetching

   Server components can fetch data directly on the server before rendering.

2. Step 2: Analyze the code behavior

   The function fetchNameFromDB() is not defined in the snippet, so this will cause a runtime error.

3. Final Answer:

   Error: fetchNameFromDB is not defined -> Option B

4. Quick Check:

   Undefined functions cause errors [OK]

Hint: Undefined functions cause errors in server components [OK]

Common Mistakes:

• Assuming fetchNameFromDB is defined
• Thinking server components can't fetch data
• Confusing client-side data fetching with server

4. You have a Next.js component that fetches user data and also handles a button click event. You mistakenly keep it as a server component. What error or issue will you face?

medium

A. The component will render twice causing performance issues.

B. The component will throw a syntax error at build time.

C. The data fetching will fail because server components cannot fetch data.

D. The button click event will not work because server components cannot handle client events.

Solution

1. Step 1: Understand event handling in Next.js components

   Only client components can handle browser events like button clicks.

2. Step 2: Identify the problem with server components

   Server components run on the server and cannot respond to client-side events, so the button click won't work.

3. Final Answer:

   The button click event will not work because server components cannot handle client events. -> Option D

4. Quick Check:

   Server components = no client events [OK]

Hint: Client events need client components [OK]

Common Mistakes:

• Expecting server components to handle clicks
• Thinking server components cause syntax errors
• Confusing data fetching ability

5. You want to build a Next.js page that shows a list of blog posts fetched from a database and includes a search box that filters posts as the user types. How should you split components between server and client?

hard

A. Keep the blog list as a server component and the search box as a client component.

B. Make both blog list and search box client components for interactivity.

C. Make both blog list and search box server components for performance.

D. Keep the search box server component and blog list client component.

Solution

1. Step 1: Identify static and interactive parts

   The blog list is static content fetched from the database, suitable for server components.

2. Step 2: Identify interactive UI needs

   The search box needs to respond to user typing, so it must be a client component.

3. Step 3: Combine components properly

   Use server component for data fetching and rendering list, client component for search input and filtering.

4. Final Answer:

   Keep the blog list as a server component and the search box as a client component. -> Option A

5. Quick Check:

   Static data = server, interactive UI = client [OK]

Hint: Static content server, interactive UI client [OK]

Common Mistakes:

• Making everything client component unnecessarily
• Trying to handle user input in server component
• Mixing up which part fetches data