Proyectos de Subversion LeadersLinked - Antes de SPA

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

export const useNear = ({ rootMargin = '0px' }) => {

  const [isNear, setIsNear] = useState(false)

  const el = useRef(null)

  useEffect(

    function () {

      if (typeof el.current === 'undefined') return

      let observer

      Promise.resolve(

        typeof window.IntersectionObserver !== 'undefined'

          ? window.IntersectionObserver

          : import('intersection-observer')

      ).then(() => {

        const onIntersect = (entries, observer) => {

          const { isIntersecting } = entries[0]

          if (isIntersecting) {

            setIsNear(true)

            observer.disconnect()

          }

        }

        observer = new window.IntersectionObserver(onIntersect, { rootMargin })

        observer.observe(el.current)

      })

      return () => observer && observer.disconnect()

    },

    [el, rootMargin]

  )

  return [isNear, el]

}