diff --git a/js/forum/src/components/IndexPage.js b/js/forum/src/components/IndexPage.js
index c48fb7020..8fedbfbb0 100644
--- a/js/forum/src/components/IndexPage.js
+++ b/js/forum/src/components/IndexPage.js
@@ -143,7 +143,7 @@ export default class IndexPage extends Page {
    */
   sidebarItems() {
     const items = new ItemList();
-    const canStartDiscussion = app.forum.canStartDiscussion() || !app.session.user;
+    const canStartDiscussion = app.forum.attribute('canStartDiscussion') || !app.session.user;
 
     items.add('newDiscussion',
       Button.component({
diff --git a/js/lib/Component.js b/js/lib/Component.js
index 8f36306ea..1de36640f 100644
--- a/js/lib/Component.js
+++ b/js/lib/Component.js
@@ -34,7 +34,7 @@ export default class Component {
    * @param {Array|Object} children
    * @public
    */
-  constructor(props = {}, children) {
+  constructor(props = {}, children = null) {
     if (children) props.children = children;
 
     this.constructor.initProps(props);
@@ -158,6 +158,7 @@ export default class Component {
    *
    * @see https://lhorie.github.io/mithril/mithril.component.html
    * @param {Object} [props] Properties to set on the component
+   * @param children
    * @return {Object} The Mithril component object
    * @property {function} controller
    * @property {function} view
@@ -165,7 +166,7 @@ export default class Component {
    * @property {Object} props The props that were passed to the component
    * @public
    */
-  static component(props = {}, children) {
+  static component(props = {}, children = null) {
     const componentProps = Object.assign({}, props);
 
     if (children) componentProps.children = children;
diff --git a/js/lib/Model.js b/js/lib/Model.js
index 23c4597be..6d7fa0ca2 100644
--- a/js/lib/Model.js
+++ b/js/lib/Model.js
@@ -10,7 +10,7 @@ export default class Model {
    * @param {Store} store The data store that this model should be persisted to.
    * @public
    */
-  constructor(data = {}, store) {
+  constructor(data = {}, store = null) {
     /**
      * The resource object from the API.
      *
diff --git a/js/lib/models/Discussion.js b/js/lib/models/Discussion.js
index 472caf895..210286075 100644
--- a/js/lib/models/Discussion.js
+++ b/js/lib/models/Discussion.js
@@ -5,7 +5,9 @@ import ItemList from 'flarum/utils/ItemList';
 import { slug } from 'flarum/utils/string';
 import Badge from 'flarum/components/Badge';
 
-export default class Discussion extends mixin(Model, {
+export default class Discussion extends Model {}
+
+Object.assign(Discussion.prototype, {
   title: Model.attribute('title'),
   slug: computed('title', slug),
 
@@ -35,8 +37,8 @@ export default class Discussion extends mixin(Model, {
   canReply: Model.attribute('canReply'),
   canRename: Model.attribute('canRename'),
   canHide: Model.attribute('canHide'),
-  canDelete: Model.attribute('canDelete')
-}) {
+  canDelete: Model.attribute('canDelete'),
+
   /**
    * Remove a post from the discussion's posts relationship.
    *
@@ -55,7 +57,7 @@ export default class Discussion extends mixin(Model, {
         }
       });
     }
-  }
+  },
 
   /**
    * Get the estimated number of unread posts in this discussion for the current
@@ -72,7 +74,7 @@ export default class Discussion extends mixin(Model, {
     }
 
     return 0;
-  }
+  },
 
   /**
    * Get the Badge components that apply to this discussion.
@@ -88,7 +90,7 @@ export default class Discussion extends mixin(Model, {
     }
 
     return items;
-  }
+  },
 
   /**
    * Get a list of all of the post IDs in this discussion.
@@ -99,4 +101,6 @@ export default class Discussion extends mixin(Model, {
   postIds() {
     return this.data.relationships.posts.data.map(link => link.id);
   }
-}
+});
+
+export default Discussion;
diff --git a/js/lib/models/Forum.js b/js/lib/models/Forum.js
index bdda47170..00e0119db 100644
--- a/js/lib/models/Forum.js
+++ b/js/lib/models/Forum.js
@@ -1,9 +1,7 @@
 import Model from 'flarum/Model';
 import mixin from 'flarum/utils/mixin';
 
-export default class Forum extends mixin(Model, {
-  canStartDiscussion: Model.attribute('canStartDiscussion')
-}) {
+export default class Forum extends Model {
   apiEndpoint() {
     return '/forum';
   }
diff --git a/js/lib/models/Group.js b/js/lib/models/Group.js
index 31be54173..1a1a6c645 100644
--- a/js/lib/models/Group.js
+++ b/js/lib/models/Group.js
@@ -1,12 +1,14 @@
 import Model from 'flarum/Model';
 import mixin from 'flarum/utils/mixin';
 
-class Group extends mixin(Model, {
+class Group extends Model {}
+
+Object.assign(Group.prototype, {
   nameSingular: Model.attribute('nameSingular'),
   namePlural: Model.attribute('namePlural'),
   color: Model.attribute('color'),
   icon: Model.attribute('icon')
-}) {}
+});
 
 Group.ADMINISTRATOR_ID = '1';
 Group.GUEST_ID = '2';
diff --git a/js/lib/models/Notification.js b/js/lib/models/Notification.js
index c50d8393c..7a03acbc7 100644
--- a/js/lib/models/Notification.js
+++ b/js/lib/models/Notification.js
@@ -2,7 +2,9 @@ import Model from 'flarum/Model';
 import mixin from 'flarum/utils/mixin';
 import computed from 'flarum/utils/computed';
 
-export default class Notification extends mixin(Model, {
+export default class Notification extends Model {}
+
+Object.assign(Notification.prototype, {
   contentType: Model.attribute('contentType'),
   subjectId: Model.attribute('subjectId'),
   content: Model.attribute('content'),
@@ -15,4 +17,6 @@ export default class Notification extends mixin(Model, {
   user: Model.hasOne('user'),
   sender: Model.hasOne('sender'),
   subject: Model.hasOne('subject')
-}) {}
+});
+
+export default Notification;
\ No newline at end of file
diff --git a/js/lib/models/Post.js b/js/lib/models/Post.js
index f8e91b9ef..43b6d5156 100644
--- a/js/lib/models/Post.js
+++ b/js/lib/models/Post.js
@@ -3,7 +3,9 @@ import mixin from 'flarum/utils/mixin';
 import computed from 'flarum/utils/computed';
 import { getPlainContent } from 'flarum/utils/string';
 
-export default class Post extends mixin(Model, {
+export default class Post extends Model {}
+
+Object.assign(Post.prototype, {
   number: Model.attribute('number'),
   discussion: Model.hasOne('discussion'),
 
@@ -24,4 +26,6 @@ export default class Post extends mixin(Model, {
 
   canEdit: Model.attribute('canEdit'),
   canDelete: Model.attribute('canDelete')
-}) {}
+});
+
+export default Post;
diff --git a/js/lib/models/User.js b/js/lib/models/User.js
index 7e3fb5b9e..a1b231654 100644
--- a/js/lib/models/User.js
+++ b/js/lib/models/User.js
@@ -7,7 +7,9 @@ import ItemList from 'flarum/utils/ItemList';
 import computed from 'flarum/utils/computed';
 import GroupBadge from 'flarum/components/GroupBadge';
 
-export default class User extends mixin(Model, {
+export default class User extends Model {}
+
+Object.assign(User.prototype, {
   username: Model.attribute('username'),
   email: Model.attribute('email'),
   isActivated: Model.attribute('isActivated'),
@@ -45,8 +47,8 @@ export default class User extends mixin(Model, {
     }
 
     return '#' + stringToColor(username);
-  })
-}) {
+  }),
+
   /**
    * Check whether or not the user has been seen in the last 5 minutes.
    *
@@ -55,7 +57,7 @@ export default class User extends mixin(Model, {
    */
   isOnline() {
     return this.lastSeenTime() > moment().subtract(5, 'minutes').toDate();
-  }
+  },
 
   /**
    * Get the Badge components that apply to this user.
@@ -73,7 +75,7 @@ export default class User extends mixin(Model, {
     }
 
     return items;
-  }
+  },
 
   /**
    * Calculate the dominant color of the user's avatar. The dominant color will
@@ -92,7 +94,7 @@ export default class User extends mixin(Model, {
       m.redraw();
     };
     image.src = this.avatarUrl();
-  }
+  },
 
   /**
    * Update the user's preferences.
@@ -107,4 +109,6 @@ export default class User extends mixin(Model, {
 
     return this.save({preferences});
   }
-}
+});
+
+export default User;