convert activities.js to es6 class syntax

app/assets/javascripts/activities.js.es6

-/* eslint-disable func-names, space-before-function-paren, wrap-iife, no-undef, quotes, no-var, padded-blocks, max-len */
-(function() {
-  this.Activities = (function() {
-    function Activities() {
+/* eslint-disable no-param-reassign, class-methods-use-this */
+/* global Pager, Cookies */
+
+((global) => {
+  class Activities {
+    constructor() {
       Pager.init(20, true, false, this.updateTooltips);
-      $(".event-filter-link").on("click", (function(_this) {
-        return function(event) {
-          event.preventDefault();
-          _this.toggleFilter($(event.currentTarget));
-          return _this.reloadActivities();
-        };
-      })(this));
+      $('.event-filter-link').on('click', (event) => {
+        event.preventDefault();
+        this.toggleFilter($(event.currentTarget));
+        this.reloadActivities();
+      });
     }
-    Activities.prototype.updateTooltips = function() {
+    updateTooltips() {
       gl.utils.localTimeAgo($('.js-timeago', '.content_list'));
-    };
-    Activities.prototype.reloadActivities = function() {
-      $(".content_list").html('');
+    }
+    reloadActivities() {
+      $('.content_list').html('');
       Pager.init(20, true, false, this.updateTooltips);
-    };
-
-    Activities.prototype.toggleFilter = function(sender) {
-      var filter = sender.attr("id").split("_")[0];
-
-      $('.event-filter .active').removeClass("active");
-      Cookies.set("event_filter", filter);
-      sender.closest('li').toggleClass("active");
-    };
-    return Activities;
-  })();
-}).call(this);
+    }
+    toggleFilter(sender) {
+      const filter = sender.attr('id').split('_')[0];
+      $('.event-filter .active').removeClass('active');
+      Cookies.set('event_filter', filter);
+      sender.closest('li').toggleClass('active');
+    }
+  }
+  global.Activities = Activities;
+})(window.gl || (window.gl = {}));

app/assets/javascripts/dispatcher.js.es6

@@ -110,10 +110,10 @@
           Issuable.init();
           break;
         case 'dashboard:activity':
-          new Activities();
+          new gl.Activities();
           break;
         case 'dashboard:projects:starred':
-          new Activities();
+          new gl.Activities();
           break;
         case 'projects:commit:show':
           new Commit();
@@ -139,7 +139,7 @@
           new gl.Pipelines();
           break;
         case 'groups:activity':
-          new Activities();
+          new gl.Activities();
           break;
         case 'groups:show':
           shortcut_handler = new ShortcutsNavigation();

app/assets/javascripts/user_tabs.js.es6

@@ -134,7 +134,7 @@ content on the Users#show page.
       }
       const $calendarWrap = this.$parentEl.find('.user-calendar');
       $calendarWrap.load($calendarWrap.data('href'));
-      new Activities();
+      new gl.Activities();
       return this.loaded['activity'] = true;
     }

app/views/projects/_activity.html.haml

@@ -13,7 +13,7 @@
   = spinner
 :javascript
-  var activity = new Activities();
+  var activity = new gl.Activities();
   $(document).on('page:restore', function (event) {
     activity.reloadActivities()
   })

spec/javascripts/activities_spec.js.es6

@@ -35,7 +35,7 @@
   describe('Activities', () => {
     beforeEach(() => {
       fixture.load(fixtureTemplate);
-      new Activities();
+      new gl.Activities();
     });
     for(let i = 0; i < filters.length; i++) {