Scroll behavior control in NextJS

Introduction

Scroll behavior control lets you decide how the page moves when users click links or buttons. It helps make navigation smooth and clear.

When you want smooth scrolling to a section after clicking a link.

When you want to jump instantly to the top of the page after an action.

When you want to control scroll position after navigating between pages.

When you want to improve user experience by avoiding sudden jumps.

When you want to restore scroll position on back/forward browser actions.

Syntax

NextJS

window.scrollTo({ top: number, left: number, behavior: 'auto' | 'smooth' })

Use behavior: 'smooth' for smooth scrolling animation.

Coordinates top and left are in pixels from the page start.

Examples

Instantly scrolls to the top-left corner of the page.

NextJS

window.scrollTo({ top: 0, left: 0, behavior: 'auto' })

Smoothly scrolls down 500 pixels from the top.

NextJS

window.scrollTo({ top: 500, left: 0, behavior: 'smooth' })

Automatically scrolls to top smoothly after page navigation in Next.js.

NextJS

import { useEffect } from 'react';
import { useRouter } from 'next/router';

export default function ScrollToTop() {
  const router = useRouter();

  useEffect(() => {
    const handleRouteChange = () => {
      window.scrollTo({ top: 0, left: 0, behavior: 'smooth' });
    };

    router.events.on('routeChangeComplete', handleRouteChange);
    return () => {
      router.events.off('routeChangeComplete', handleRouteChange);
    };
  }, [router.events]);

  return null;
}

Sample Program

This Next.js component shows a button that, when clicked, smoothly scrolls down to a section far below. The section is focusable for accessibility.

NextJS

import { useRef } from 'react';

export default function ScrollExample() {
  const sectionRef = useRef(null);

  function scrollToSection() {
    sectionRef.current?.scrollIntoView({ behavior: 'smooth' });
  }

  return (
    <main style={{ height: '150vh', padding: '1rem' }}>
      <button onClick={scrollToSection} aria-label="Scroll to section">
        Go to Section
      </button>
      <div style={{ marginTop: '100vh', padding: '1rem', backgroundColor: '#def' }} ref={sectionRef} tabIndex={-1} aria-label="Target section">
        <h2>Target Section</h2>
        <p>This is the section you scrolled to smoothly.</p>
      </div>
    </main>
  );
}

Important Notes

Use scrollIntoView on elements for easy smooth scrolling to parts of the page.

Remember to add aria-label and tabIndex for accessibility when scrolling to sections.

Test scroll behavior on different browsers as support may vary slightly.

Summary

Scroll behavior control improves how users move around your page.

Use window.scrollTo or element.scrollIntoView with behavior: 'smooth' for smooth scrolling.

In Next.js, you can listen to route changes to control scroll position after navigation.

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