docs: function safeEndingTags(content) {
    var MJElements = [].concat(WHITELISTED_GLOBAL_TAG);
  
    (0, _forEach2.default)(_extends({}, _MJMLElementsCollection2.default, _MJMLHead2.default), function (element, name) {
      var tagName = element.tagName || name;
  
      MJElements.push(tagName);
    });
  
    var safeContent = (0, _parseAttributes2.default)(MJElements, content.replace(/\$/g, '&#36;'));
  
    (0, _concat2.default)(_MJMLElementsCollection.endingTags, _MJMLHead.endingTags).forEach(function (tag) {
      safeContent = safeContent.replace(regexTag(tag), _dom2.default.replaceContentByCdata(tag));
    });
  
    return safeContent;
  }