rootMargin doesn't work when root default to null

[iamyoki]

See this example in codesandbox

https://codesandbox.io/s/try-react-infinite-scroll-hook-4ekfj1?file=/src/App.jsx:1374-1384

This is a common pitfall when using rootMargin without root specified

Little rules of Interception Observer API：
root default to viewport while the viewport doesn't have any margin, so set rootMargin to any value will always fallback to 0px .

[iamyoki]

I may implemented a better version of this hook

Easier to use, less properties required, same ability, here is a simple usage:

export default function App() {
  const [list, setList] = useState([...Array(11).keys()])
  const { containerRef, isLoading } = useInfiniteScroll({
    async onLoadMore() {
      const res = await fetchList(list.slice(-1)[0])
      setList(list.concat(res))
    },
  })

  return (
    <div className="App">
      <List ref={containerRef}>
        {list.map((n) => (
          <Item key={n}>{n}</Item>
        ))}
        {isLoading && <Loading>Loading ...</Loading>}
      </List>
    </div>
  )

Use offset against rootMargin

Will load more while to bottom offset '200px'

const { containerRef, isLoading } = useInfiniteScroll({offset: '200px'})
...

All css size units available

• offset: 200px ✅
• offset: 20% ✅
• offset: 20vh ✅
• offset: 20cm ✅
• ...

Extra bonus

Using offset: 200px as absolute distance to bottom offset.
Using offset: 20% as relative distance to bottom offset, it will insure the trigger point always stick to the 80% height of scrollbar.

Stop while finished

const { containerRef, isLoading } = useInfiniteScroll({shouldStop: isFetchEnd})
...

return (
    <div className="App">
      <List ref={containerRef}>
        {list.map((n) => (
          <Item key={n}>{n}</Item>
        ))}
        {(isLoading || !isFetchEnd) && <Loading>Loading ...</Loading>}
      </List>
    </div>
  )

Talk is cheap, check out the source code :)

https://codesandbox.io/s/better-react-infinite-scroll-hook-kgup0w?file=/src/useInfiniteScroll.js

[iamyoki]

Update the next day:

I made it to become another independent library https://github.com/iamyoki/infinite-scroll-hook