【React hooks】要素の変化を検知して何かをするカスタムフックを作成する | ツクログ

import { useEffect } from '../preact@10.5.13/hooks.js';

export const useMutationObserver = (elements, callback, config) => 
  useEffect(() => {
    const mutationObserver = new MutationObserver((mutations) => {
      mutationObserver.disconnect();
      callback(mutations);
      for (const elem of elements) {
        elem.current && mutationObserver.observe(elem.current, config);
      }
    });

    for (const elem of elements) {
      elem.current && mutationObserver.observe(elem.current, config);
    }

    return () => mutationObserver.disconnect();
  }, []);
