diff -u b/core/misc/message.es6.js b/core/misc/message.es6.js
--- b/core/misc/message.es6.js
+++ b/core/misc/message.es6.js
@@ -21,7 +21,7 @@
    *   Object to add and remove messages.
    */
 
-  Drupal.message = class Message {
+  Drupal.message = class {
     constructor(messageWrapper = document.querySelector('[data-drupal-messages]')) {
       this.messageWrapper = messageWrapper;
       if (!this.messageWrapper) {
@@ -83,12 +83,12 @@
     }
 
     /**
-     * Select a set of messages based on type or index.
+     * Select a set of messages based on index.
      *
      * @name Drupal.message~messageDefinition.select
      *
      * @param {string|Array.<string>} index
-     *   The message index or type to delete from the area.
+     *   The message index to delete from the area.
      *
      * @return {NodeList|Array}
      *   Elements found.
diff -u b/core/misc/message.js b/core/misc/message.js
--- b/core/misc/message.js
+++ b/core/misc/message.js
@@ -11,10 +11,10 @@
 (function (Drupal) {
 
   Drupal.message = function () {
-    function Message() {
+    function _class() {
       var messageWrapper = arguments.length > 0 && arguments[0] !== undefined ? arguments[0] : document.querySelector('[data-drupal-messages]');
 
-      _classCallCheck(this, Message);
+      _classCallCheck(this, _class);
 
       this.messageWrapper = messageWrapper;
       if (!this.messageWrapper) {
@@ -22,7 +22,7 @@
       }
     }
 
-    _createClass(Message, [{
+    _createClass(_class, [{
       key: 'add',
       value: function add(message) {
         var options = arguments.length > 1 && arguments[1] !== undefined ? arguments[1] : {};
@@ -107,7 +107,7 @@
       }
     }]);
 
-    return Message;
+    return _class;
   }();
 
   Drupal.theme.message = function (message, options) {