react-infinite-scroll-hook

react-infinite-scroll-hook

This is a hook to create infinite scroll components!
Live demo is here.

Basically, we need to set a sentry component to trigger infinite loading. When sentry becomes visible on the screen or it comes near to be visible (based on our config of course), it triggers infinite loading (by calling onLoadMore callback) all with the help of IntersectionObserver.

sentry should be some component which will not be unmounted as long as we want to keep the infinite scrolling observer active. For example, we can use a "loading" indicator as our sentry. The trick is, because that we want to keep the infinite scrolling observer active as long as there is a next page, we need to keep this "loading" component mounted even if we don't have a loading flag as true. This will also keep our layout more consistent and prevent flickering etc.

We don't need to use a "loading" component as the sentry and we can keep them separate too. It can be anything like some empty div or last item of your list etc. We just need to place it based on our scrolling direction. To bottom if we want to trigger loading when we scroll to bottom, to top if we want to trigger it when we scroll to top like a chat message box etc. Same approach can be used with horizontal scrolling too.

Please check below to find examples with different layouts and libraries.

Note: This package uses IntersectionObserver under the hood. You might want to check the browser compatibility from here and if you want to support older browsers, you might need to use a polyfill.

Before v4, useInfiniteScroll hook would basically check the DOM with an interval and look at the distance between the bottom of your "infinite" component and the bottom of the window. This was a simple solution. But it had its difficulties. It was not so easy to change the layout of your "infinite" component (like creating a chat message box with inverted scrolling etc). It was a requirement to modify the package based on each different use case.

And also, checking the DOM with an interval by using setInterval wasn't a sophisticated solution. It was enough, but it had it's limits. With v4, we migrated to use IntersectionObserver and created a much more flexible API to support different design. Basically, now we have a little bit more inversion of control.

If you want to use the older version which is using setInterval, you can find it here.

Installation

npm install react-infinite-scroll-hook

Simple Example

import useInfiniteScroll from 'react-infinite-scroll-hook';

function SimpleInfiniteList() {
  const { loading, items, hasNextPage, error, loadMore } = useLoadItems();

  const [sentryRef] = useInfiniteScroll({
    loading,
    hasNextPage,
    onLoadMore: loadMore,
    // When there is an error, we stop infinite loading.
    // It can be reactivated by setting "error" state as undefined.
    disabled: !!error,
    // `rootMargin` is passed to `IntersectionObserver`.
    // We can use it to trigger 'onLoadMore' when the sentry comes near to become
    // visible, instead of becoming fully visible on the screen.
    rootMargin: '0px 0px 400px 0px',
  });

  return (
    <List>
      {items.map((item) => (
        <ListItem key={item.key}>{item.value}</ListItem>
      ))}
      {/* 
          As long as we have a "next page", we show "Loading" right under the list.
          When it becomes visible on the screen, or it comes near, it triggers 'onLoadMore'.
          This is our "sentry".
          We can also use another "sentry" which is separated from the "Loading" component like:
            <div ref={sentryRef} />
            {loading && <ListItem>Loading...</ListItem>}
          and leave "Loading" without this ref.
      */}
      {(loading || hasNextPage) && (
        <ListItem ref={sentryRef}>
          <Loading />
        </ListItem>
      )}
    </List>
  );
}

Or if we have a scrollable container and we want to use it as our "list container" instead of document, we just need to use rootRef like:

function InfiniteListWithVerticalScroll() {
  const { loading, items, hasNextPage, error, loadMore } = useLoadItems();

  const [sentryRef, { rootRef }] = useInfiniteScroll({
    loading,
    hasNextPage,
    onLoadMore: loadMore,
    disabled: !!error,
    rootMargin: '0px 0px 400px 0px',
  });

  return (
    <ListContainer
      // This where we set our scrollable root component.
      ref={rootRef}
    >
      <List>
        {items.map((item) => (
          <ListItem key={item.key}>{item.value}</ListItem>
        ))}
        {(loading || hasNextPage) && (
          <ListItem ref={sentryRef}>
            <Loading />
          </ListItem>
        )}
      </List>
    </ListContainer>
  );
}

Other Examples

You can find different layout examples here. Live demo contains all of these cases.

Also, we have more realistinc examples with swr and Apollo GraphQL too.

Arguments

Name	Description	Type	Optional	Default Value
loading	Some sort of "is fetching" info of the request.	boolean	❌
hasNextPage	If the list has more items to load.	boolean	❌
onLoadMore	The callback function to execute when the 'onLoadMore' is triggered.	VoidFunction	❌
rootMargin	We pass this to 'IntersectionObserver'. We can use it to configure when to trigger 'onLoadMore'.	string	✅
disabled	Flag to stop infinite scrolling. Can be used in case of an error etc too.	boolean	✅
delayInMs	How long it should wait before triggering 'onLoadMore' (in milliseconds).	number	✅	100

Contributors ✨

Thanks goes to these wonderful people (emoji key):

Eugene Fidelin 💻

Evan Cater 📖

This project follows the all-contributors specification. Contributions of any kind welcome!