SmoothScroller.md

Smooth Scroller for React

It's a port of Sooth Scroller for Svelte for React.

Actually, it requires GSAP, TypeScript & Tailwindcss are optional.

To remove TypeScript, just remove the type marks. To remove Tailwindcss, remove tailwindclasses but don't forget to reproduce the same styles in the elements with pure CSS.

Dependencies:

• GSAP (optional)
• Tailwindcss (optional)

Details

This example depends on GSAP to perform scroll y position across many browsers. It could be replaced by any function that resolves scroll position for all browsers to cover with.

Taiwindcss classes has been used here too. It could be replaced with respective styles.

Svelte component based on sample at: https://codepen.io/osublake/pen/QqPqbN

Usage

<SmoothScroller>
  {/* your scrollable content here */}
</SmoothScroller>

Live Example

Codesandbox

MIT License

SmoothScroller.tsx

/*
  Smooth scroller
  
  Just add any scrollable container inside this component.

  Dependencies:
  
  This example depends on GSAP to perform scroll y position across many browsers. It could
  be replaced by any function that resolves scroll position for all browsers to cover with.
  Taiwindcss classes has been used here too. It could be replaced with respective styles.
  
  MIT License
  Copyright (c) 2020 Jan Cassio
  Permission is hereby granted, free of charge, to any person obtaining a copy
  of this software and associated documentation files (the "Software"), to deal
  in the Software without restriction, including without limitation the rights
  to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
  copies of the Software, and to permit persons to whom the Software is
  furnished to do so, subject to the following conditions:
  The above copyright notice and this permission notice shall be included in all
  copies or substantial portions of the Software.
  THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
  IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
  AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
  LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
  OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
  SOFTWARE.
*/

import gsap from 'gsap'
import { useEffect, useRef } from 'react'

type Props = { children?: ReactNode }

export default function SmoothScroller(props: Props): JSX.Element {
  const { children } = props
  const container = useRef(null)

  useEffect(() => {
    const html = document.documentElement
    const body = document.body
    const ease = 0.1
    const target = container.current

    let y = 0
    let resizeRequest = 1
    let scrollRequest = 0
    let requestId: number

    gsap.config({ force3D: true })

    function render(): void {
      requestId = requestAnimationFrame(update)
    }

    function update(): void {
      resizeHeightIfNeeded()
      const scrollY = window.pageYOffset || html.scrollTop || body.scrollTop || 0

      y += (scrollY - y) * ease
      gsap.set(target, { y: -y })
      requestId = scrollRequest > 0 ? requestAnimationFrame(update) : null
      scrollRequest--
    }

    function bodyResize(): void {
      const height = target.clientHeight
      body.style.height = `${height}px`
    }

    function resizeHeightIfNeeded(): void {
      const resized = resizeRequest > 0

      if (resized) {
        bodyResize()
        resizeRequest = 0
      }
    }

    function onScroll(): void {
      scrollRequest++

      if (!requestId) {
        render()
      }
    }

    function onResize(): void {
      resizeRequest++
      if (!requestId) {
        render()
      }
    }

    window.focus()
    window.addEventListener('resize', onResize)
    document.addEventListener('scroll', onScroll)
    document.addEventListener('wheel', onScroll)

    return () => {
      window.addEventListener('resize', onResize)
      document.addEventListener('scroll', onScroll)
      document.addEventListener('wheel', onScroll)
    }
  }, [])

  return (
    <div className="viewport overflow-hidden fixed inset-0 w-full h-full">
      <div ref={container}>{children}</div>
    </div>
  )
}