When to keep components on server in NextJS - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to mark a component as a server component in Next.js.

NextJS

"use client" directive is used to mark a component as a client component. To keep it on the server, we do not use [1].

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

A"use client"

B"server component"

C"use server"

D"client component"

Attempts:

3 left

💡 Hint

Common Mistakes

Using "use client" to keep a component on the server.

Not understanding that server components are default.

In Next.js, server components are the default. To explicitly mark a component as a client component, you use "use client". There is no directive needed to keep it on the server; simply do not use "use client".

2fill in blank

medium

Complete the code to import a client component inside a server component in Next.js.

NextJS

import ClientComponent from './ClientComponent';

export default function ServerComponent() {
  return <[1] />;
}

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

Aclientcomponent

BServerComponent

CclientComponent

DClientComponent

Attempts:

3 left

💡 Hint

Common Mistakes

Using lowercase or incorrect casing for component names.

Trying to use a server component name instead.

You import the client component by its exact name and use it as a JSX tag inside the server component.

3fill in blank

hard

Identify the React hook causing the error in this server component.

NextJS

export default function ServerComponent() {
  const [count, setCount] = [1](0);
  return <p>{count}</p>;
}

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

AuseState

BuseEffect

CuseRef

DuseMemo

Attempts:

3 left

💡 Hint

Common Mistakes

Trying to use hooks in server components.

Not understanding the difference between server and client components.

React hooks like useState cannot be used in server components because they run only on the server. This causes an error. To fix, you must remove hooks or convert the component to a client component.

4fill in blank

hard

Fill both blanks to create a server component that fetches data and renders it.

NextJS

export default async function DataComponent() {
  const data = await fetch('/api/data').then(res => res.[1]());
  return <div>{data.[2]</div>;
}

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

Ajson

Btext

Cvalue

Ddata

Attempts:

3 left

💡 Hint

Common Mistakes

Using res.text() instead of res.json().

Trying to render the whole data object directly.

To get JSON data from a fetch response, use res.json(). Then access the needed property from the data object to render.

5fill in blank

hard

Fill all three blanks to create a client component that updates state and calls a server action.

NextJS

"use client";

import { useState } from 'react';
import { serverAction } from './actions';

export default function ClientUpdater() {
  const [value, setValue] = useState('');

  async function handleClick() {
    await serverAction([1]);
  }

  return (
    <button onClick={() => setValue([2])} onClickCapture={handleClick}>
      [3]
    </button>
  );
}

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

Avalue

B'new value'

CClick me

DsetValue

Attempts:

3 left

💡 Hint

Common Mistakes

Passing the setter function instead of the value to serverAction.

Using incorrect event handlers or button text.

The server action is called with the current value. The state is updated with a new string. The button text is set to "Click me".

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