export default function getOffsetTop(element, container) {
  if (!element) {
    return 0;
  }

  if (!element.getClientRects().length) {
    return 0;
  }

  var rect = element.getBoundingClientRect();

  if (rect.width || rect.height) {
    if (container === window) {
      container = element.ownerDocument.documentElement;
      return rect.top - container.clientTop;
    }

    return rect.top - container.getBoundingClientRect().top;
  }

  return rect.top;
}