useIntersection

Observe element intersection with Intersection Observer API.

Import


import { useIntersection } from '@tidbcloud/uikit'

Usage

useIntersection returns information about the intersection of a given element with its scroll container or body element.


import { useIntersection } from '@tidbcloud/uikit'
import { Box, Text } from '@tidbcloud/uikit'
 
function Demo() {
  const { ref, entry } = useIntersection({
    root: null,
    threshold: 0.5
  })
 
  return (
    <>
      <Text>{entry?.isIntersecting ? 'Element is visible' : 'Scroll to see element'}</Text>
      <div style={{ height: '150vh' }} />
      <Box ref={ref} p="xl" bg={entry?.isIntersecting ? 'green' : 'red'}>
        Target element ({Math.round((entry?.intersectionRatio || 0) * 100)}% visible)
      </Box>
    </>
  )
}

API

The hook accepts IntersectionObserver options as its only argument:


import { useIntersection } from '@tidbcloud/uikit'
 
useIntersection({
  root: document.querySelector('#some-element'),
  rootMargin: '0px',
  threshold: 1.0
})

On the first render (as well as during SSR), or when no element is being observed, the entry is null.

Definition


interface UseIntersectionReturnValue<T> {
  ref: React.RefCallback<T | null>
  entry: IntersectionObserverEntry | null
}
 
function useIntersection<T extends HTMLElement = any>(options?: IntersectionObserverInit): UseIntersectionReturnValue<T>