code: function disableDocumentScrolling(element) {
    if (!document.documentElement) {
      return;
    }
    const documentWidth = document.documentElement.clientWidth;
    const scrollBarWidth = window.innerWidth - documentWidth;
    element[previousBodyOverflowKey] = document.body.style.overflow;
    element[previousDocumentMarginRightKey] = scrollBarWidth > 0 ?
      document.documentElement.style.marginRight :
      null;
    document.body.style.overflow = 'hidden';
    if (scrollBarWidth > 0) {
      document.documentElement.style.marginRight = `${scrollBarWidth}px`;
    }
  }
docs: Mark body as non-scrollable, to absorb space bar keypresses and other means of scrolling the top-level document.