Checker for overflowed elements on page

check-overflow.js

function styleReverter(elem, style, value) {
  const valueBefore = elem.style[style];

  elem.style[style] = value;

  return () => {
    elem.style[style] = valueBefore;
  }
}

function testOverflow(elem) {
  const styles = window.getComputedStyle(elem);
  const overflowX = styles.overflowX;

  if (overflowX !== 'visible') return false;

  const windowWidthBefore = window.innerWidth;

  if (styles.display !== 'none') {
    const displayReverter = styleReverter(elem, 'display', 'none');

    const isResized = windowWidthBefore !== window.innerWidth;

    displayReverter();

    return isResized;
  }
}

function iterateOverflowDom(elem = document.body) {
  const isOverflowed = testOverflow(elem);

  if (!isOverflowed) return [];

  const childs = [...elem.childNodes];

  const result = childs.reduce((acc, elem) => {
    if (elem.nodeType !== 1) return acc;
    
    return acc.concat(iterateOverflowDom(elem));
  }, []);

  if (result.length === 0) {
    return [elem]
  };

  return result;
}