code: function isValidElement(o) {
    return (
      typeof HTMLElement === "object" ? o instanceof HTMLElement : //DOM2
        o && typeof o === "object" && o !== null && o.nodeType === 1 && typeof o.nodeName==="string" && o.nodeName.toLowerCase() === 'a-entity'
    );
  }
docs: Returns true if it is a DOM element with nodeName a-entity https://stackoverflow.com/a/384380/2835973