Scroll behavior control in NextJS - Cheat Sheet & Quick Revision

Recall & Review

beginner

What is scroll behavior control in Next.js?

Scroll behavior control in Next.js means managing how the page moves up or down when users navigate between pages or interact with the site. It helps create smooth or instant scrolling effects.

intermediate

How do you enable smooth scrolling when navigating between pages in Next.js?

You can enable smooth scrolling by using the scroll option in the router.push() method or by adding CSS scroll-behavior: smooth; to the page container.

intermediate

What does setting scroll: false in router.push() do?

Setting scroll: false prevents Next.js from automatically scrolling to the top of the page after navigation. This keeps the scroll position where it was before the page changed.

advanced

How can you scroll to a specific element after navigation in Next.js?

You can scroll to a specific element by using a hash in the URL (like /page#section) and then using useEffect to find that element and call element.scrollIntoView() after the page loads.

beginner

Why is controlling scroll behavior important for user experience?

Controlling scroll behavior helps users keep their place on the page, avoid sudden jumps, and enjoy smooth transitions. This makes the website feel polished and easier to use.

In Next.js, what does router.push('/about', undefined, { scroll: false }) do?

A Navigates to /about without scrolling to top

B Navigates to /about and scrolls to top

C Prevents navigation to /about

D Reloads the current page

The option scroll: false tells Next.js not to scroll to the top after navigation.

Which CSS property enables smooth scrolling behavior on a page?

A overflow: hidden;

B scroll-snap-type: mandatory;

C scrollbar-width: thin;

D scroll-behavior: smooth;

The CSS property scroll-behavior: smooth; makes scrolling transitions smooth.

How can you scroll to a specific section after navigation in Next.js?

A Use router.reload()

B Set scroll: false in router.push() only

C Use a URL hash and scrollIntoView in useEffect

D Use window.alert()

Using a URL hash and then calling scrollIntoView() in a React effect scrolls to the target element.

What is the default scroll behavior after navigation in Next.js?

A Scrolls to the top of the page

B Keeps the current scroll position

C Scrolls to the bottom of the page

D Scrolls to a random position

By default, Next.js scrolls to the top after navigation.

Why might you want to disable automatic scrolling on navigation?

A To prevent navigation

B To keep the user's scroll position when updating content

C To speed up page loading

D To disable scrolling completely

Disabling automatic scroll helps keep the user's place on the page, improving experience.

Explain how to control scroll behavior when navigating between pages in Next.js.

Think about navigation methods and how to scroll smoothly or keep position.

Describe why managing scroll behavior improves user experience on websites.

Consider how users feel when pages jump or scroll unexpectedly.

Practice

1. What does setting behavior: 'smooth' in window.scrollTo do in a Next.js app?

easy

A. It reloads the page after scrolling.

B. It makes the page scroll smoothly instead of jumping instantly.

C. It scrolls the page to the top instantly.

D. It disables scrolling on the page.

Solution

1. Step 1: Understand the scroll behavior option

   The behavior property controls how scrolling happens. Setting it to 'smooth' means the scroll moves gradually.

2. Step 2: Apply to Next.js scrolling

   Using window.scrollTo({ behavior: 'smooth' }) in Next.js makes the page scroll smoothly instead of jumping instantly.

3. Final Answer:

   It makes the page scroll smoothly instead of jumping instantly. -> Option B

4. Quick Check:

   behavior: 'smooth' = smooth scrolling [OK]

Hint: Remember 'smooth' means gradual scroll, not instant jump [OK]

Common Mistakes:

• Thinking 'smooth' disables scrolling
• Confusing 'smooth' with instant scroll
• Assuming it reloads the page

2. Which of the following is the correct syntax to scroll smoothly to the top of the page in Next.js?

easy

A. window.scrollTo({ smooth: 'top' });

B. window.scrollTo(0, 0, 'smooth');

C. window.scrollTo({ top: 0, smooth: true });

D. window.scrollTo({ top: 0, behavior: 'smooth' });

Solution

1. Step 1: Review window.scrollTo syntax

   The correct syntax uses an object with top and behavior keys: { top: 0, behavior: 'smooth' }.

2. Step 2: Identify correct option

   window.scrollTo({ top: 0, behavior: 'smooth' }); matches the correct syntax. Others misuse parameters or keys.

3. Final Answer:

   window.scrollTo({ top: 0, behavior: 'smooth' }); -> Option D

4. Quick Check:

   Correct scrollTo syntax = window.scrollTo({ top: 0, behavior: 'smooth' }); [OK]

Hint: Use object with top and behavior keys for smooth scroll [OK]

Common Mistakes:

• Passing parameters as separate arguments instead of object
• Using incorrect keys like 'smooth' instead of 'behavior'
• Misplacing the 'smooth' value

3. Consider this Next.js code snippet inside a component:
<pre>useEffect(() => { router.events.on('routeChangeComplete', () => { window.scrollTo({ top: 0, behavior: 'smooth' }); }); }, []);
What will happen when the route changes?

medium

A. The page will smoothly scroll to the top after navigation.

B. Nothing will happen because the event listener is not removed.

C. The page will jump instantly to the top.

D. The page will reload after scrolling.

Solution

1. Step 1: Understand event listener on routeChangeComplete

   The code listens for the route change completion event and triggers scrolling.

2. Step 2: Analyze scrollTo call

   It calls window.scrollTo with behavior: 'smooth', so scrolling is smooth to top.

3. Final Answer:

   The page will smoothly scroll to the top after navigation. -> Option A

4. Quick Check:

   routeChangeComplete + smooth scroll = smooth scroll top [OK]

Hint: routeChangeComplete triggers smooth scroll to top [OK]

Common Mistakes:

• Assuming instant jump instead of smooth scroll
• Thinking event listener removal is required to trigger scroll
• Confusing scroll with page reload

4. This Next.js code tries to scroll smoothly on route change:
<pre>useEffect(() => { router.events.on('routeChangeComplete', () => { window.scrollTo({ top: 0, behavior: 'smooth' }); }); }, []);
But after navigating multiple times, scrolling stops working. What is the likely problem?

medium

A. The event listener is added multiple times without cleanup, causing issues.

B. The scrollTo syntax is incorrect and causes errors.

C. Next.js does not support scroll control on route changes.

D. The behavior 'smooth' is not supported in modern browsers.

Solution

1. Step 1: Identify event listener management

   The code adds an event listener on mount but never removes it, so multiple listeners accumulate.

2. Step 2: Understand effect of multiple listeners

   Multiple listeners cause unexpected behavior or conflicts, stopping scroll from working properly.

3. Final Answer:

   The event listener is added multiple times without cleanup, causing issues. -> Option A

4. Quick Check:

   Missing cleanup causes multiple listeners = problem [OK]

Hint: Always remove event listeners in useEffect cleanup [OK]

Common Mistakes:

• Ignoring cleanup of event listeners
• Blaming scrollTo syntax which is correct
• Assuming browser support is the issue

5. You want to scroll smoothly to a specific section with id 'contact' after navigating to a new page in Next.js. Which approach correctly achieves this?

hard

A. Use window.scrollTo(0, 0); after navigation and then call scrollIntoView without behavior option.

B. Use window.scrollTo({ top: document.getElementById('contact').offsetTop, behavior: 'auto' }); inside routeChangeStart event.

C. Use router.events.on('routeChangeComplete', () => { document.getElementById('contact').scrollIntoView({ behavior: 'smooth' }); });

D. Use router.push('/contact'); without any scroll control; rely on default browser behavior.

Solution

1. Step 1: Choose correct event and method

   Use routeChangeComplete to ensure page is loaded, then scroll to element with smooth behavior.

2. Step 2: Verify scrollIntoView usage

   scrollIntoView({ behavior: 'smooth' }) scrolls smoothly to the element with id 'contact'.

3. Final Answer:

   Use router.events.on('routeChangeComplete', () => { document.getElementById('contact').scrollIntoView({ behavior: 'smooth' }); }); -> Option C

4. Quick Check:

   routeChangeComplete + scrollIntoView smooth = Use router.events.on('routeChangeComplete', () => { document.getElementById('contact').scrollIntoView({ behavior: 'smooth' }); }); [OK]

Hint: Scroll after routeChangeComplete using scrollIntoView with smooth [OK]

Common Mistakes:

• Using routeChangeStart instead of routeChangeComplete
• Forgetting behavior: 'smooth' for smooth scroll
• Relying on default scroll without control