Server-side state passing in NextJS - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to export a server component that receives props.

NextJS

export default function Page({ [1] }) {
  return <h1>{message}</h1>;
}

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

Adata

Bprops

Cstate

Dmessage

Attempts:

3 left

💡 Hint

Common Mistakes

Using 'props' without destructuring causes undefined variable error.

Using 'state' or 'data' which are not passed as props.

The component receives message as a prop and uses it inside JSX.

2fill in blank

medium

Complete the code to fetch data on the server and pass it as props.

NextJS

export default async function Page() {
  const data = await fetch('/api/data').then(res => res.json());
  return <h1>{data.[1]</h1>;
}

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

Atext

Btitle

Cmessage

Dcontent

Attempts:

3 left

💡 Hint

Common Mistakes

Using a wrong property name causes undefined to show.

Trying to access data without awaiting fetch.

The fetched JSON has a message property used in JSX.

3fill in blank

hard

Fix the error in passing server data to a client component.

NextJS

import ClientComponent from './ClientComponent';

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

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

Adata={data}

Bprops=data

Cdata:data

Ddata

Attempts:

3 left

💡 Hint

Common Mistakes

Passing props without key causes syntax errors.

Using colon instead of equal sign in JSX.

Props must be passed as data={data} to the client component.

4fill in blank

hard

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

NextJS

import ClientComponent from './ClientComponent';

export default async function Page() {
  const [1] = await fetch('/api/info').then(res => res.json());
  return <ClientComponent [2]=[1] />;
}

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

Ainfo

Bdata

DinfoData

Attempts:

3 left

💡 Hint

Common Mistakes

Using different names for variable and prop without mapping.

Forgetting to await fetch causes errors.

The variable info holds fetched data and is passed as prop info.

5fill in blank

hard

Fill all three blanks to pass server data as props and render it in a client component.

NextJS

import ClientComponent from './ClientComponent';

export default async function Page() {
  const [1] = await fetch('/api/user').then(res => res.json());
  return <ClientComponent [2]=[1] [3]="active" />;
}

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

Auser

Cstatus

Dstate

Attempts:

3 left

💡 Hint

Common Mistakes

Mixing up variable and prop names.

Using curly braces for string literals.

The fetched data is stored in user, passed as prop user, and a string prop status is set to "active".

Practice

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

easy

A. To manage browser cookies

B. To handle client-side routing

C. To style components dynamically

D. To fetch data on the server before rendering the page

Solution

1. Step 1: Understand getServerSideProps role

   This function runs on the server before the page loads to fetch or prepare data.

2. Step 2: Identify its main use

   It ensures the page has fresh data on first load and improves SEO by server-side rendering.

3. Final Answer:

   To fetch data on the server before rendering the page -> Option D

4. Quick Check:

   Server-side data fetching = A [OK]

Hint: Remember: server-side means before page shows [OK]

Common Mistakes:

• Confusing client-side routing with server-side data fetching
• Thinking it styles components
• Assuming it manages cookies directly

2. Which of the following is the correct syntax to export getServerSideProps in a Next.js page?

easy

A. export default getServerSideProps = () => ({ props: {} })

B. export async function getServerSideProps(context) { return { props: {} } }

C. function getServerSideProps() { return props: {} }

D. export getServerSideProps = async () => { return {} }

Solution

1. Step 1: Recall correct export syntax

   getServerSideProps must be an async function exported with the exact name.

2. Step 2: Check return structure

   It returns an object with a props key containing data for the page.

3. Final Answer:

   export async function getServerSideProps(context) { return { props: {} } } -> Option B

4. Quick Check:

   Correct async export with props = D [OK]

Hint: Use async function with named export and return props [OK]

Common Mistakes:

• Using arrow function without export keyword
• Returning object without wrapping props
• Using default export incorrectly

3. Given this code snippet in a Next.js page, what will be the rendered output?

export async function getServerSideProps() {
  return { props: { message: 'Hello from server' } };
}

export default function Page({ message }) {
  return <h1>{message}</h1>;
}

medium

A. <h1>Hello from server</h1>

B. Error: message is undefined

C. <h1>{message}</h1>

D. <h1>Hello from client</h1>

Solution

1. Step 1: Understand data flow

   getServerSideProps passes message as a prop to the page component.

2. Step 2: Render output

   The component receives message and renders it inside an <h1> tag.

3. Final Answer:

   <h1>Hello from server</h1> -> Option A

4. Quick Check:

   Server prop passed and rendered = A [OK]

Hint: Props from server appear as component parameters [OK]

Common Mistakes:

• Thinking props are undefined without client fetch
• Rendering literal {message} instead of value
• Confusing server message with client message

4. What is wrong with this getServerSideProps function?

export async function getServerSideProps() {
  const data = await fetch('https://api.example.com/data');
  return data;
}

medium

A. The returned props must be an object with a props key wrapping data

B. The fetch call is missing await

C. getServerSideProps cannot be async

D. The function should return data directly, not inside props

Solution

1. Step 1: Check fetch usage

   The fetch is awaited correctly, so no issue there.

2. Step 2: Check return structure

   The function must return an object with a props key containing an object. Here, data is returned directly, which is incorrect.

3. Final Answer:

   The returned props must be an object with a props key wrapping data -> Option A

4. Quick Check:

   Return { props: { ... } } not just data [OK]

Hint: Always wrap data inside props object in return [OK]

Common Mistakes:

• Returning data directly instead of inside props
• Forgetting to await fetch
• Thinking async is not allowed

5. You want to pass user data fetched from a database to a Next.js page using getServerSideProps. Which approach correctly handles the asynchronous fetch and passes the data safely to the page component?

hard

A. export async function getServerSideProps() {
const user = getUserFromDB();
return { props: user };
}

B. export function getServerSideProps() {
const user = getUserFromDB();
return { props: { user } };
}

C. export async function getServerSideProps() {
const user = await getUserFromDB();
return { props: { user } };
}

D. export async function getServerSideProps() {
const user = await getUserFromDB();
return user;
}

Solution

1. Step 1: Handle async data fetching

   The function must be async and await the database call to get user data.

2. Step 2: Return data wrapped in props object

   The returned object must have a props key containing an object with user data.

3. Final Answer:

   export async function getServerSideProps() { const user = await getUserFromDB(); return { props: { user } }; } -> Option C

4. Quick Check:

   Async await + return props object = C [OK]

Hint: Await async fetch and wrap result inside props [OK]

Common Mistakes:

• Not awaiting async database call
• Returning data directly without props wrapper
• Using non-async function for async fetch