Function isDescendant

src/utils/dom.js:11–22

(parent, child)

}

export function isDescendant (parent, child) {
  let node = child.parentNode;

  while (node !== null) {
    if (node === parent) {
      return true;
    }
    node = node.parentNode;
  }

  return false;
}

export function offset (el) {
  const rect = el.getBoundingClientRect();