@ash/use-intersection-observer v1.0.0

useIntersectionObserver

npm i @ash/use-intersection-observer

Most Intersection Observer helpers are geared towards tracking a single element. This hook is designed for observing multiple elements.

Usage

The useIntersectionObserver hook returns an object with the following entries:

addRef: (component, id: EntryId) => void

Call addRef from a component ref to begin tracking the underlying HTML element.

EntryId is a string or number used to uniquely identify the HTML element.

intersecting: Set

A Set containing all of the EntryIds that are currently intersecting.

Example

import useIntersectionObserver from 'use-intersection-observer'

const App = () => {
  const { addRef, intersecting } = useIntersectionObserver()
  const users = ['Louise', 'Bob', 'Linda']

  return (
    <ul>
      {users.map(name => (
        <li
          key={name}
          ref={component => addRef(component, name)}
        >
          {name}
        </li>
      ))}
    </ul>
  )
}