Server-side state passing in NextJS - Cheat Sheet & Quick Revision

Recall & Review

beginner

What is server-side state passing in Next.js?

It means sending data from the server to the client during page rendering, so the page loads with the needed information already available.

beginner

Which Next.js function is commonly used to fetch data on the server before rendering a page?

getServerSideProps is used to fetch data on the server at request time and pass it as props to the page component.

intermediate

How does getServerSideProps help with SEO?

Because data is fetched on the server and included in the HTML sent to the browser, search engines can see the full content immediately.

intermediate

What is the difference between getServerSideProps and getStaticProps in Next.js?

getServerSideProps runs on every request to fetch fresh data, while getStaticProps runs at build time to generate static pages.

advanced

Why should you avoid putting sensitive information directly in the props returned by getServerSideProps?

Because props are sent to the client and can be seen by users, sensitive data should be kept secure and not exposed in props.

Which Next.js function fetches data on the server for each request?

A useEffect

B getStaticProps

C getServerSideProps

D getInitialProps

getServerSideProps runs on the server at every request to fetch data.

What does server-side state passing improve in a Next.js app?

A Page load speed and SEO

B Client-side animations

C Browser caching

D CSS styling

Passing state from server helps pages load faster with data and improves SEO by sending full HTML.

Where is the data returned by getServerSideProps available?

A As props in the page component

B Only in the browser console

C In the CSS files

D In the database

Data returned by getServerSideProps is passed as props to the page component.

Which method runs only once at build time in Next.js?

A getInitialProps

B getStaticProps

C useEffect

D getServerSideProps

getStaticProps runs once at build time to generate static pages.

Why avoid sending sensitive data in server-side props?

A Props cannot be accessed by the client

B Props are encrypted automatically

C Props are stored only on the server

D Props are visible to users in the browser

Props are sent to the client and can be viewed, so sensitive data should not be included.

Explain how server-side state passing works in Next.js and why it is useful.

Think about how data is prepared before the page reaches the browser.

Describe the difference between getServerSideProps and getStaticProps in Next.js.

Consider when the data is fetched and how often.

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