code: function windowBottomScrollbarHeight(): number {
    let out = 0;
    // May be SSR, hence try
    try {
      const { body } = document;
      if (body && body.scrollWidth > window.innerWidth) {
        out = getScrollbarWidth();
      }
    } catch (err) {
      /* ignore */
    }
    return out;
  }
docs: ========================================== Widths, heights... ==========================================