customAttribute = (attributeName, caller, ref) => {
  if ( ref === void 0 ) ref = {};
  var allowedTags = ref.allowedTags;
  var addToElement = ref.addToElement;

  return GLOBALS.CUSTOM_ATTRIBUTES[attributeName] = {
  name: attributeName,
  caller,
  allowedTags: allowedTags || null,
  addToElement,
};
}
@param {string} attributeName
@param {function} caller
@param {object} object
@returns {object}