@kiwicom/orbit-components/es/hooks/useIntersect/index.js

Orbit-components is a React component library which provides developers with the easiest possible way of building Kiwi.com’s products.

import { useState, useEffect, useRef, useCallback } from "react";
const useIntersect = ({
  root = null,
  rootMargin,
  threshold = 0
} = {}) => {
  const [entry, updateEntry] = useState(null);
  const [node, setNode] = useState(null);
  const ref = useCallback(el => {
    setNode(el);
  }, []);
  const observer = useRef(null);
  useEffect(() => {
    if ("IntersectionObserver" in window === false) return () => {};
    observer.current = new window.IntersectionObserver(([ent]) => updateEntry(ent), {
      root,
      rootMargin,
      threshold
    });
    const {
      current: currentObs
    } = observer;
    if (node) currentObs?.observe(node);
    return () => currentObs?.disconnect();
  }, [node, root, rootMargin, threshold]);
  return {
    ref,
    entry,
    observer: observer.current
  };
};
export default useIntersect;