diff --git a/app/assets/javascripts/discourse/app/models/action-summary.js b/app/assets/javascripts/discourse/app/models/action-summary.js
index 6554d0ccd38..3b8ce55cbb6 100644
--- a/app/assets/javascripts/discourse/app/models/action-summary.js
+++ b/app/assets/javascripts/discourse/app/models/action-summary.js
@@ -3,8 +3,8 @@ import { ajax } from "discourse/lib/ajax";
 import { popupAjaxError } from "discourse/lib/ajax-error";
 import RestModel from "discourse/models/rest";
 
-export default RestModel.extend({
-  canToggle: or("can_undo", "can_act"),
+export default class ActionSummary extends RestModel {
+  @or("can_undo", "can_act") canToggle;
 
   // Remove it
   removeAction() {
@@ -14,11 +14,11 @@ export default RestModel.extend({
       can_act: true,
       can_undo: false,
     });
-  },
+  }
 
   togglePromise(post) {
     return this.acted ? this.undo(post) : this.act(post);
-  },
+  }
 
   toggle(post) {
     if (!this.acted) {
@@ -28,7 +28,7 @@ export default RestModel.extend({
       this.undo(post);
       return false;
     }
-  },
+  }
 
   // Perform this action
   act(post, opts) {
@@ -76,7 +76,7 @@ export default RestModel.extend({
         popupAjaxError(error);
         this.removeAction(post);
       });
-  },
+  }
 
   // Undo this action
   undo(post) {
@@ -90,5 +90,5 @@ export default RestModel.extend({
       post.updateActionsSummary(result);
       return { acted: false };
     });
-  },
-});
+  }
+}
diff --git a/app/assets/javascripts/discourse/app/models/archetype.js b/app/assets/javascripts/discourse/app/models/archetype.js
index bd4eedffe0b..6f9e60ecc48 100644
--- a/app/assets/javascripts/discourse/app/models/archetype.js
+++ b/app/assets/javascripts/discourse/app/models/archetype.js
@@ -2,8 +2,8 @@ import { gt, not } from "@ember/object/computed";
 import { propertyEqual } from "discourse/lib/computed";
 import RestModel from "discourse/models/rest";
 
-export default RestModel.extend({
-  hasOptions: gt("options.length", 0),
-  isDefault: propertyEqual("id", "site.default_archetype"),
-  notDefault: not("isDefault"),
-});
+export default class Archetype extends RestModel {
+  @gt("options.length", 0) hasOptions;
+  @propertyEqual("id", "site.default_archetype") isDefault;
+  @not("isDefault") notDefault;
+}
diff --git a/app/assets/javascripts/discourse/app/models/associated-group.js b/app/assets/javascripts/discourse/app/models/associated-group.js
index e914aaf824e..b5de9175d1e 100644
--- a/app/assets/javascripts/discourse/app/models/associated-group.js
+++ b/app/assets/javascripts/discourse/app/models/associated-group.js
@@ -2,16 +2,12 @@ import EmberObject from "@ember/object";
 import { ajax } from "discourse/lib/ajax";
 import { popupAjaxError } from "discourse/lib/ajax-error";
 
-const AssociatedGroup = EmberObject.extend();
-
-AssociatedGroup.reopenClass({
-  list() {
+export default class AssociatedGroup extends EmberObject {
+  static list() {
     return ajax("/associated_groups")
       .then((result) => {
         return result.associated_groups.map((ag) => AssociatedGroup.create(ag));
       })
       .catch(popupAjaxError);
-  },
-});
-
-export default AssociatedGroup;
+  }
+}
diff --git a/app/assets/javascripts/discourse/app/models/badge-grouping.js b/app/assets/javascripts/discourse/app/models/badge-grouping.js
index 9e668bef95c..e60b79f5ea7 100644
--- a/app/assets/javascripts/discourse/app/models/badge-grouping.js
+++ b/app/assets/javascripts/discourse/app/models/badge-grouping.js
@@ -2,15 +2,15 @@ import RestModel from "discourse/models/rest";
 import discourseComputed from "discourse-common/utils/decorators";
 import I18n from "discourse-i18n";
 
-export default RestModel.extend({
+export default class BadgeGrouping extends RestModel {
   @discourseComputed("name")
   i18nNameKey() {
     return this.name.toLowerCase().replace(/\s/g, "_");
-  },
+  }
 
   @discourseComputed("name")
   displayName() {
     const i18nKey = `badges.badge_grouping.${this.i18nNameKey}.name`;
     return I18n.t(i18nKey, { defaultValue: this.name });
-  },
-});
+  }
+}
diff --git a/app/assets/javascripts/discourse/app/models/badge.js b/app/assets/javascripts/discourse/app/models/badge.js
index 01c369418fc..bf0f0afb5a7 100644
--- a/app/assets/javascripts/discourse/app/models/badge.js
+++ b/app/assets/javascripts/discourse/app/models/badge.js
@@ -7,63 +7,8 @@ import RestModel from "discourse/models/rest";
 import getURL from "discourse-common/lib/get-url";
 import discourseComputed from "discourse-common/utils/decorators";
 
-const Badge = RestModel.extend({
-  newBadge: none("id"),
-  image: alias("image_url"),
-
-  @discourseComputed
-  url() {
-    return getURL(`/badges/${this.id}/${this.slug}`);
-  },
-
-  updateFromJson(json) {
-    if (json.badge) {
-      Object.keys(json.badge).forEach((key) => this.set(key, json.badge[key]));
-    }
-    if (json.badge_types) {
-      json.badge_types.forEach((badgeType) => {
-        if (badgeType.id === this.badge_type_id) {
-          this.set("badge_type", Object.create(badgeType));
-        }
-      });
-    }
-  },
-
-  @discourseComputed("badge_type.name")
-  badgeTypeClassName(type) {
-    type = type || "";
-    return `badge-type-${type.toLowerCase()}`;
-  },
-
-  save(data) {
-    let url = "/admin/badges",
-      type = "POST";
-
-    if (this.id) {
-      // We are updating an existing badge.
-      url += `/${this.id}`;
-      type = "PUT";
-    }
-
-    return ajax(url, { type, data }).then((json) => {
-      this.updateFromJson(json);
-      return this;
-    });
-  },
-
-  destroy() {
-    if (this.newBadge) {
-      return Promise.resolve();
-    }
-
-    return ajax(`/admin/badges/${this.id}`, {
-      type: "DELETE",
-    });
-  },
-});
-
-Badge.reopenClass({
-  createFromJson(json) {
+export default class Badge extends RestModel {
+  static createFromJson(json) {
     // Create BadgeType objects.
     const badgeTypes = {};
     if ("badge_types" in json) {
@@ -103,9 +48,9 @@ Badge.reopenClass({
     } else {
       return badges;
     }
-  },
+  }
 
-  findAll(opts) {
+  static findAll(opts) {
     let listable = "";
     if (opts && opts.onlyListable) {
       listable = "?only_listable=true";
@@ -114,13 +59,65 @@ Badge.reopenClass({
     return ajax(`/badges.json${listable}`, { data: opts }).then((badgesJson) =>
       Badge.createFromJson(badgesJson)
     );
-  },
+  }
 
-  findById(id) {
+  static findById(id) {
     return ajax(`/badges/${id}`).then((badgeJson) =>
       Badge.createFromJson(badgeJson)
     );
-  },
-});
+  }
 
-export default Badge;
+  @none("id") newBadge;
+
+  @alias("image_url") image;
+
+  @discourseComputed
+  url() {
+    return getURL(`/badges/${this.id}/${this.slug}`);
+  }
+
+  updateFromJson(json) {
+    if (json.badge) {
+      Object.keys(json.badge).forEach((key) => this.set(key, json.badge[key]));
+    }
+    if (json.badge_types) {
+      json.badge_types.forEach((badgeType) => {
+        if (badgeType.id === this.badge_type_id) {
+          this.set("badge_type", Object.create(badgeType));
+        }
+      });
+    }
+  }
+
+  @discourseComputed("badge_type.name")
+  badgeTypeClassName(type) {
+    type = type || "";
+    return `badge-type-${type.toLowerCase()}`;
+  }
+
+  save(data) {
+    let url = "/admin/badges",
+      type = "POST";
+
+    if (this.id) {
+      // We are updating an existing badge.
+      url += `/${this.id}`;
+      type = "PUT";
+    }
+
+    return ajax(url, { type, data }).then((json) => {
+      this.updateFromJson(json);
+      return this;
+    });
+  }
+
+  destroy() {
+    if (this.newBadge) {
+      return Promise.resolve();
+    }
+
+    return ajax(`/admin/badges/${this.id}`, {
+      type: "DELETE",
+    });
+  }
+}
diff --git a/app/assets/javascripts/discourse/app/models/bookmark.js b/app/assets/javascripts/discourse/app/models/bookmark.js
index 26c11f3cd9b..8898862a8ae 100644
--- a/app/assets/javascripts/discourse/app/models/bookmark.js
+++ b/app/assets/javascripts/discourse/app/models/bookmark.js
@@ -25,13 +25,33 @@ export const AUTO_DELETE_PREFERENCES = {
 export const NO_REMINDER_ICON = "bookmark";
 export const WITH_REMINDER_ICON = "discourse-bookmark-clock";
 
-const Bookmark = RestModel.extend({
-  newBookmark: none("id"),
+export default class Bookmark extends RestModel {
+  static create(args) {
+    args = args || {};
+    args.currentUser = args.currentUser || User.current();
+    args.user = User.create(args.user);
+    return super.create(args);
+  }
+
+  static createFor(user, bookmarkableType, bookmarkableId) {
+    return Bookmark.create({
+      bookmarkable_type: bookmarkableType,
+      bookmarkable_id: bookmarkableId,
+      user_id: user.id,
+      auto_delete_preference: user.user_option.bookmark_auto_delete_preference,
+    });
+  }
+
+  static async applyTransformations(bookmarks) {
+    await applyModelTransformations("bookmark", bookmarks);
+  }
+
+  @none("id") newBookmark;
 
   @computed
   get url() {
     return getURL(`/bookmarks/${this.id}`);
-  },
+  }
 
   destroy() {
     if (this.newBookmark) {
@@ -41,14 +61,14 @@ const Bookmark = RestModel.extend({
     return ajax(this.url, {
       type: "DELETE",
     });
-  },
+  }
 
   attachedTo() {
     return {
       target: this.bookmarkable_type.toLowerCase(),
       targetId: this.bookmarkable_id,
     };
-  },
+  }
 
   togglePin() {
     if (this.newBookmark) {
@@ -58,16 +78,16 @@ const Bookmark = RestModel.extend({
     return ajax(this.url + "/toggle_pin", {
       type: "PUT",
     });
-  },
+  }
 
   pinAction() {
     return this.pinned ? "unpin" : "pin";
-  },
+  }
 
   @discourseComputed("highest_post_number", "url")
   lastPostUrl(highestPostNumber) {
     return this.urlForPostNumber(highestPostNumber);
-  },
+  }
 
   // Helper to build a Url with a post number
   urlForPostNumber(postNumber) {
@@ -76,7 +96,7 @@ const Bookmark = RestModel.extend({
       url += `/${postNumber}`;
     }
     return url;
-  },
+  }
 
   // returns createdAt if there's no bumped date
   @discourseComputed("bumped_at", "createdAt")
@@ -86,7 +106,7 @@ const Bookmark = RestModel.extend({
     } else {
       return createdAt;
     }
-  },
+  }
 
   @discourseComputed("bumpedAt", "createdAt")
   bumpedAtTitle(bumpedAt, createdAt) {
@@ -101,7 +121,7 @@ const Bookmark = RestModel.extend({
           })}\n${I18n.t("topic.bumped_at", { date: longDate(bumpedAt) })}`
         : I18n.t("topic.created_at", { date: longDate(createdAt) });
     }
-  },
+  }
 
   @discourseComputed("name", "reminder_at")
   reminderTitle(name, reminderAt) {
@@ -118,12 +138,12 @@ const Bookmark = RestModel.extend({
     return I18n.t("bookmarks.created_generic", {
       name: name || "",
     });
-  },
+  }
 
   @discourseComputed("created_at")
   createdAt(created_at) {
     return new Date(created_at);
-  },
+  }
 
   @discourseComputed("tags")
   visibleListTags(tags) {
@@ -141,12 +161,12 @@ const Bookmark = RestModel.extend({
     });
 
     return newTags;
-  },
+  }
 
   @computed("category_id")
   get category() {
     return Category.findById(this.category_id);
-  },
+  }
 
   @discourseComputed("reminder_at", "currentUser")
   formattedReminder(bookmarkReminderAt, currentUser) {
@@ -156,12 +176,12 @@ const Bookmark = RestModel.extend({
         currentUser?.user_option?.timezone || moment.tz.guess()
       )
     );
-  },
+  }
 
   @discourseComputed("reminder_at")
   reminderAtExpired(bookmarkReminderAt) {
     return moment(bookmarkReminderAt) < moment();
-  },
+  }
 
   @discourseComputed()
   topicForList() {
@@ -178,34 +198,10 @@ const Bookmark = RestModel.extend({
       last_read_post_number: this.last_read_post_number,
       highest_post_number: this.highest_post_number,
     });
-  },
+  }
 
   @discourseComputed("bookmarkable_type")
   bookmarkableTopicAlike(bookmarkable_type) {
     return ["Topic", "Post"].includes(bookmarkable_type);
-  },
-});
-
-Bookmark.reopenClass({
-  create(args) {
-    args = args || {};
-    args.currentUser = args.currentUser || User.current();
-    args.user = User.create(args.user);
-    return this._super(args);
-  },
-
-  createFor(user, bookmarkableType, bookmarkableId) {
-    return Bookmark.create({
-      bookmarkable_type: bookmarkableType,
-      bookmarkable_id: bookmarkableId,
-      user_id: user.id,
-      auto_delete_preference: user.user_option.bookmark_auto_delete_preference,
-    });
-  },
-
-  async applyTransformations(bookmarks) {
-    await applyModelTransformations("bookmark", bookmarks);
-  },
-});
-
-export default Bookmark;
+  }
+}
diff --git a/app/assets/javascripts/discourse/app/models/category-list.js b/app/assets/javascripts/discourse/app/models/category-list.js
index 2311eed3a7c..eefc465af89 100644
--- a/app/assets/javascripts/discourse/app/models/category-list.js
+++ b/app/assets/javascripts/discourse/app/models/category-list.js
@@ -8,38 +8,8 @@ import Topic from "discourse/models/topic";
 import { bind } from "discourse-common/utils/decorators";
 import I18n from "discourse-i18n";
 
-const CategoryList = ArrayProxy.extend({
-  init() {
-    this.set("content", this.categories || []);
-    this._super(...arguments);
-    this.set("page", 1);
-    this.set("fetchedLastPage", false);
-  },
-
-  @bind
-  async loadMore() {
-    if (this.isLoading || this.fetchedLastPage) {
-      return;
-    }
-
-    this.set("isLoading", true);
-
-    const data = { page: this.page + 1 };
-    const result = await ajax("/categories.json", { data });
-
-    this.set("page", data.page);
-    if (result.category_list.categories.length === 0) {
-      this.set("fetchedLastPage", true);
-    }
-    this.set("isLoading", false);
-
-    const newCategoryList = CategoryList.categoriesFrom(this.store, result);
-    newCategoryList.forEach((c) => this.categories.pushObject(c));
-  },
-});
-
-CategoryList.reopenClass({
-  categoriesFrom(store, result, parentCategory = null) {
+export default class CategoryList extends ArrayProxy {
+  static categoriesFrom(store, result, parentCategory = null) {
     // Find the period that is most relevant
     const statPeriod =
       ["week", "month"].find(
@@ -67,9 +37,9 @@ CategoryList.reopenClass({
       }
     });
     return categories;
-  },
+  }
 
-  _buildCategoryResult(c, statPeriod) {
+  static _buildCategoryResult(c, statPeriod) {
     if (c.parent_category_id) {
       c.parentCategory = Category.findById(c.parent_category_id);
     }
@@ -126,9 +96,9 @@ CategoryList.reopenClass({
     const record = Site.current().updateCategory(c);
     record.setupGroupsAndPermissions();
     return record;
-  },
+  }
 
-  listForParent(store, category) {
+  static listForParent(store, category) {
     return ajax(
       `/categories.json?parent_category_id=${category.get("id")}`
     ).then((result) =>
@@ -138,9 +108,9 @@ CategoryList.reopenClass({
         parentCategory: category,
       })
     );
-  },
+  }
 
-  list(store) {
+  static list(store) {
     return PreloadStore.getAndRemove("categories_list", () =>
       ajax("/categories.json")
     ).then((result) =>
@@ -151,7 +121,33 @@ CategoryList.reopenClass({
         can_create_topic: result.category_list.can_create_topic,
       })
     );
-  },
-});
+  }
 
-export default CategoryList;
+  init() {
+    this.set("content", this.categories || []);
+    super.init(...arguments);
+    this.set("page", 1);
+    this.set("fetchedLastPage", false);
+  }
+
+  @bind
+  async loadMore() {
+    if (this.isLoading || this.fetchedLastPage) {
+      return;
+    }
+
+    this.set("isLoading", true);
+
+    const data = { page: this.page + 1 };
+    const result = await ajax("/categories.json", { data });
+
+    this.set("page", data.page);
+    if (result.category_list.categories.length === 0) {
+      this.set("fetchedLastPage", true);
+    }
+    this.set("isLoading", false);
+
+    const newCategoryList = CategoryList.categoriesFrom(this.store, result);
+    newCategoryList.forEach((c) => this.categories.pushObject(c));
+  }
+}
diff --git a/app/assets/javascripts/discourse/app/models/category.js b/app/assets/javascripts/discourse/app/models/category.js
index c4e36382ec3..f15bd040237 100644
--- a/app/assets/javascripts/discourse/app/models/category.js
+++ b/app/assets/javascripts/discourse/app/models/category.js
@@ -14,370 +14,9 @@ import { MultiCache } from "discourse-common/utils/multi-cache";
 const STAFF_GROUP_NAME = "staff";
 const CATEGORY_ASYNC_SEARCH_CACHE = {};
 
-const Category = RestModel.extend({
-  permissions: null,
-
-  @on("init")
-  setupGroupsAndPermissions() {
-    const availableGroups = this.available_groups;
-    if (!availableGroups) {
-      return;
-    }
-    this.set("availableGroups", availableGroups);
-
-    const groupPermissions = this.group_permissions;
-
-    if (groupPermissions) {
-      this.set(
-        "permissions",
-        groupPermissions.map((elem) => {
-          availableGroups.removeObject(elem.group_name);
-          return elem;
-        })
-      );
-    }
-  },
-
-  @discourseComputed("required_tag_groups", "minimum_required_tags")
-  minimumRequiredTags() {
-    if (this.required_tag_groups?.length > 0) {
-      // it should require the max between the bare minimum set in the category and the sum of the min_count of the
-      // required_tag_groups
-      return Math.max(
-        this.required_tag_groups.reduce((sum, rtg) => sum + rtg.min_count, 0),
-        this.minimum_required_tags || 0
-      );
-    } else {
-      return this.minimum_required_tags > 0 ? this.minimum_required_tags : null;
-    }
-  },
-
-  @discourseComputed
-  availablePermissions() {
-    return [
-      PermissionType.create({ id: PermissionType.FULL }),
-      PermissionType.create({ id: PermissionType.CREATE_POST }),
-      PermissionType.create({ id: PermissionType.READONLY }),
-    ];
-  },
-
-  @discourseComputed("id")
-  searchContext(id) {
-    return { type: "category", id, category: this };
-  },
-
-  @discourseComputed("parentCategory.ancestors")
-  ancestors(parentAncestors) {
-    return [...(parentAncestors || []), this];
-  },
-
-  @discourseComputed("parentCategory.level")
-  level(parentLevel) {
-    if (!parentLevel) {
-      return parentLevel === 0 ? 1 : 0;
-    } else {
-      return parentLevel + 1;
-    }
-  },
-
-  @discourseComputed("has_children", "subcategories")
-  isParent(hasChildren, subcategories) {
-    return hasChildren || (subcategories && subcategories.length > 0);
-  },
-
-  @discourseComputed("subcategories")
-  isGrandParent(subcategories) {
-    return (
-      subcategories &&
-      subcategories.some(
-        (cat) => cat.subcategories && cat.subcategories.length > 0
-      )
-    );
-  },
-
-  @discourseComputed("notification_level")
-  isMuted(notificationLevel) {
-    return notificationLevel === NotificationLevels.MUTED;
-  },
-
-  @discourseComputed("isMuted", "subcategories")
-  isHidden(isMuted, subcategories) {
-    if (!isMuted) {
-      return false;
-    } else if (!subcategories) {
-      return true;
-    }
-
-    if (subcategories.some((cat) => !cat.isHidden)) {
-      return false;
-    }
-
-    return true;
-  },
-
-  @discourseComputed("isMuted", "subcategories")
-  hasMuted(isMuted, subcategories) {
-    if (isMuted) {
-      return true;
-    } else if (!subcategories) {
-      return false;
-    }
-
-    if (subcategories.some((cat) => cat.hasMuted)) {
-      return true;
-    }
-
-    return false;
-  },
-
-  @discourseComputed("notification_level")
-  notificationLevelString(notificationLevel) {
-    // Get the key from the value
-    const notificationLevelString = Object.keys(NotificationLevels).find(
-      (key) => NotificationLevels[key] === notificationLevel
-    );
-    if (notificationLevelString) {
-      return notificationLevelString.toLowerCase();
-    }
-  },
-
-  @discourseComputed("name")
-  path() {
-    return `/c/${Category.slugFor(this)}/${this.id}`;
-  },
-
-  @discourseComputed("path")
-  url(path) {
-    return getURL(path);
-  },
-
-  @discourseComputed
-  fullSlug() {
-    return Category.slugFor(this).replace(/\//g, "-");
-  },
-
-  @discourseComputed("name")
-  nameLower(name) {
-    return name.toLowerCase();
-  },
-
-  @discourseComputed("url")
-  unreadUrl(url) {
-    return `${url}/l/unread`;
-  },
-
-  @discourseComputed("url")
-  newUrl(url) {
-    return `${url}/l/new`;
-  },
-
-  @discourseComputed("color", "text_color")
-  style(color, textColor) {
-    return `background-color: #${color}; color: #${textColor}`;
-  },
-
-  @discourseComputed("topic_count")
-  moreTopics(topicCount) {
-    return topicCount > (this.num_featured_topics || 2);
-  },
-
-  @discourseComputed("topic_count", "subcategories.[]")
-  totalTopicCount(topicCount, subcategories) {
-    if (subcategories) {
-      subcategories.forEach((subcategory) => {
-        topicCount += subcategory.topic_count;
-      });
-    }
-    return topicCount;
-  },
-
-  @discourseComputed("default_slow_mode_seconds")
-  defaultSlowModeMinutes(seconds) {
-    return seconds ? seconds / 60 : null;
-  },
-
-  @discourseComputed("notification_level")
-  isTracked(notificationLevel) {
-    return notificationLevel >= NotificationLevels.TRACKING;
-  },
-
-  get unreadTopicsCount() {
-    return this.topicTrackingState.countUnread({ categoryId: this.id });
-  },
-
-  get newTopicsCount() {
-    return this.topicTrackingState.countNew({ categoryId: this.id });
-  },
-
-  save() {
-    const id = this.id;
-    const url = id ? `/categories/${id}` : "/categories";
-
-    return ajax(url, {
-      contentType: "application/json",
-      data: JSON.stringify({
-        name: this.name,
-        slug: this.slug,
-        color: this.color,
-        text_color: this.text_color,
-        secure: this.secure,
-        permissions: this._permissionsForUpdate(),
-        auto_close_hours: this.auto_close_hours,
-        auto_close_based_on_last_post: this.get(
-          "auto_close_based_on_last_post"
-        ),
-        default_slow_mode_seconds: this.default_slow_mode_seconds,
-        position: this.position,
-        email_in: this.email_in,
-        email_in_allow_strangers: this.email_in_allow_strangers,
-        mailinglist_mirror: this.mailinglist_mirror,
-        parent_category_id: this.parent_category_id,
-        uploaded_logo_id: this.get("uploaded_logo.id"),
-        uploaded_logo_dark_id: this.get("uploaded_logo_dark.id"),
-        uploaded_background_id: this.get("uploaded_background.id"),
-        uploaded_background_dark_id: this.get("uploaded_background_dark.id"),
-        allow_badges: this.allow_badges,
-        category_setting_attributes: this.category_setting,
-        custom_fields: this.custom_fields,
-        topic_template: this.topic_template,
-        form_template_ids: this.form_template_ids,
-        all_topics_wiki: this.all_topics_wiki,
-        allow_unlimited_owner_edits_on_first_post:
-          this.allow_unlimited_owner_edits_on_first_post,
-        allowed_tags: this.allowed_tags,
-        allowed_tag_groups: this.allowed_tag_groups,
-        allow_global_tags: this.allow_global_tags,
-        required_tag_groups: this.required_tag_groups,
-        sort_order: this.sort_order,
-        sort_ascending: this.sort_ascending,
-        topic_featured_link_allowed: this.topic_featured_link_allowed,
-        show_subcategory_list: this.show_subcategory_list,
-        num_featured_topics: this.num_featured_topics,
-        default_view: this.default_view,
-        subcategory_list_style: this.subcategory_list_style,
-        default_top_period: this.default_top_period,
-        minimum_required_tags: this.minimum_required_tags,
-        navigate_to_first_post_after_read: this.get(
-          "navigate_to_first_post_after_read"
-        ),
-        search_priority: this.search_priority,
-        reviewable_by_group_name: this.reviewable_by_group_name,
-        read_only_banner: this.read_only_banner,
-        default_list_filter: this.default_list_filter,
-      }),
-      type: id ? "PUT" : "POST",
-    });
-  },
-
-  _permissionsForUpdate() {
-    const permissions = this.permissions;
-    let rval = {};
-    if (permissions.length) {
-      permissions.forEach((p) => (rval[p.group_name] = p.permission_type));
-    } else {
-      // empty permissions => staff-only access
-      rval[STAFF_GROUP_NAME] = PermissionType.FULL;
-    }
-    return rval;
-  },
-
-  destroy() {
-    return ajax(`/categories/${this.id || this.slug}`, {
-      type: "DELETE",
-    });
-  },
-
-  addPermission(permission) {
-    this.permissions.addObject(permission);
-    this.availableGroups.removeObject(permission.group_name);
-  },
-
-  removePermission(group_name) {
-    const permission = this.permissions.findBy("group_name", group_name);
-    if (permission) {
-      this.permissions.removeObject(permission);
-      this.availableGroups.addObject(group_name);
-    }
-  },
-
-  updatePermission(group_name, type) {
-    this.permissions.forEach((p, i) => {
-      if (p.group_name === group_name) {
-        this.set(`permissions.${i}.permission_type`, type);
-      }
-    });
-  },
-
-  @discourseComputed("topics")
-  latestTopic(topics) {
-    if (topics && topics.length) {
-      return topics[0];
-    }
-  },
-
-  @discourseComputed("topics")
-  featuredTopics(topics) {
-    if (topics && topics.length) {
-      return topics.slice(0, this.num_featured_topics || 2);
-    }
-  },
-
-  setNotification(notification_level) {
-    User.currentProp(
-      "muted_category_ids",
-      User.current().calculateMutedIds(
-        notification_level,
-        this.id,
-        "muted_category_ids"
-      )
-    );
-
-    const url = `/category/${this.id}/notifications`;
-    return ajax(url, { data: { notification_level }, type: "POST" }).then(
-      (data) => {
-        User.current().set(
-          "indirectly_muted_category_ids",
-          data.indirectly_muted_category_ids
-        );
-        this.set("notification_level", notification_level);
-        this.notifyPropertyChange("notification_level");
-      }
-    );
-  },
-
-  @discourseComputed("id")
-  isUncategorizedCategory(id) {
-    return Category.isUncategorized(id);
-  },
-
-  get canCreateTopic() {
-    return this.permission === PermissionType.FULL;
-  },
-
-  get subcategoryWithCreateTopicPermission() {
-    return this.subcategories?.find(
-      (subcategory) => subcategory.canCreateTopic
-    );
-  },
-});
-
-let _uncategorized;
-
-const categoryMultiCache = new MultiCache(async (ids) => {
-  const result = await ajax("/categories/find", { data: { ids } });
-
-  return new Map(
-    result["categories"].map((category) => [category.id, category])
-  );
-});
-
-export function resetCategoryCache() {
-  categoryMultiCache.reset();
-}
-
-Category.reopenClass({
+export default class Category extends RestModel {
   // Sort subcategories directly under parents
-  sortCategories(categories) {
+  static sortCategories(categories) {
     const children = new Map();
 
     categories.forEach((category) => {
@@ -392,20 +31,20 @@ Category.reopenClass({
       values.flatMap((c) => [c, reduce(children.get(c.id) || [])]).flat();
 
     return reduce(children.get(-1) || []);
-  },
+  }
 
-  isUncategorized(categoryId) {
+  static isUncategorized(categoryId) {
     return categoryId === Site.currentProp("uncategorized_category_id");
-  },
+  }
 
-  slugEncoded() {
+  static slugEncoded() {
     let siteSettings = getOwnerWithFallback(this).lookup(
       "service:site-settings"
     );
     return siteSettings.slug_generation_method === "encoded";
-  },
+  }
 
-  findUncategorized() {
+  static findUncategorized() {
     _uncategorized =
       _uncategorized ||
       Category.list().findBy(
@@ -413,9 +52,9 @@ Category.reopenClass({
         Site.currentProp("uncategorized_category_id")
       );
     return _uncategorized;
-  },
+  }
 
-  slugFor(category, separator = "/", depth = 3) {
+  static slugFor(category, separator = "/", depth = 3) {
     if (!category) {
       return "";
     }
@@ -434,21 +73,21 @@ Category.reopenClass({
     return !slug || slug.trim().length === 0
       ? `${result}${id}-category`
       : result + slug;
-  },
+  }
 
-  list() {
+  static list() {
     return Site.currentProp("categoriesList");
-  },
+  }
 
-  listByActivity() {
+  static listByActivity() {
     return Site.currentProp("sortedCategories");
-  },
+  }
 
-  _idMap() {
+  static _idMap() {
     return Site.currentProp("categoriesById");
-  },
+  }
 
-  findSingleBySlug(slug) {
+  static findSingleBySlug(slug) {
     if (!this.slugEncoded()) {
       return Category.list().find((c) => Category.slugFor(c) === slug);
     } else {
@@ -456,16 +95,16 @@ Category.reopenClass({
         (c) => Category.slugFor(c) === encodeURI(slug)
       );
     }
-  },
+  }
 
-  findById(id) {
+  static findById(id) {
     if (!id) {
       return;
     }
     return Category._idMap()[id];
-  },
+  }
 
-  findByIds(ids = []) {
+  static findByIds(ids = []) {
     const categories = [];
     ids.forEach((id) => {
       const found = Category.findById(id);
@@ -474,14 +113,14 @@ Category.reopenClass({
       }
     });
     return categories;
-  },
+  }
 
-  hasAsyncFoundAll(ids) {
+  static hasAsyncFoundAll(ids) {
     const loadedCategoryIds = Site.current().loadedCategoryIds || new Set();
     return ids.every((id) => loadedCategoryIds.has(id));
-  },
+  }
 
-  async asyncFindByIds(ids = []) {
+  static async asyncFindByIds(ids = []) {
     ids = ids.map((x) => parseInt(x, 10));
 
     if (!Site.current().lazy_load_categories) {
@@ -508,9 +147,9 @@ Category.reopenClass({
     Site.current().set("loadedCategoryIds", loadedCategoryIds);
 
     return categories;
-  },
+  }
 
-  findBySlugAndParent(slug, parentCategory) {
+  static findBySlugAndParent(slug, parentCategory) {
     if (this.slugEncoded()) {
       slug = encodeURI(slug);
     }
@@ -520,9 +159,9 @@ Category.reopenClass({
         (category.parentCategory || null) === parentCategory
       );
     });
-  },
+  }
 
-  findBySlugPath(slugPath) {
+  static findBySlugPath(slugPath) {
     let category = null;
 
     for (const slug of slugPath) {
@@ -534,9 +173,9 @@ Category.reopenClass({
     }
 
     return category;
-  },
+  }
 
-  async asyncFindBySlugPathWithID(slugPathWithID) {
+  static async asyncFindBySlugPathWithID(slugPathWithID) {
     const result = await ajax("/categories/find", {
       data: { slug_path_with_id: slugPathWithID },
     });
@@ -546,9 +185,9 @@ Category.reopenClass({
     );
 
     return categories[categories.length - 1];
-  },
+  }
 
-  findBySlugPathWithID(slugPathWithID) {
+  static findBySlugPathWithID(slugPathWithID) {
     let parts = slugPathWithID.split("/").filter(Boolean);
     // slugs found by star/glob pathing in ember do not automatically url decode - ensure that these are decoded
     if (this.slugEncoded()) {
@@ -575,9 +214,9 @@ Category.reopenClass({
     }
 
     return category;
-  },
+  }
 
-  findBySlug(slug, parentSlug) {
+  static findBySlug(slug, parentSlug) {
     const categories = Category.list();
     let category;
 
@@ -615,34 +254,34 @@ Category.reopenClass({
     }
 
     return category;
-  },
+  }
 
-  fetchVisibleGroups(id) {
+  static fetchVisibleGroups(id) {
     return ajax(`/c/${id}/visible_groups.json`);
-  },
+  }
 
-  reloadById(id) {
+  static reloadById(id) {
     return ajax(`/c/${id}/show.json`);
-  },
+  }
 
-  reloadBySlugPath(slugPath) {
+  static reloadBySlugPath(slugPath) {
     return ajax(`/c/${slugPath}/find_by_slug.json`);
-  },
+  }
 
-  reloadCategoryWithPermissions(params, store, site) {
+  static reloadCategoryWithPermissions(params, store, site) {
     return this.reloadBySlugPath(params.slug).then((result) =>
       this._includePermissions(result.category, store, site)
     );
-  },
+  }
 
-  _includePermissions(category, store, site) {
+  static _includePermissions(category, store, site) {
     const record = store.createRecord("category", category);
     record.setupGroupsAndPermissions();
     site.updateCategory(record);
     return record;
-  },
+  }
 
-  search(term, opts) {
+  static search(term, opts) {
     let limit = 5;
     let parentCategoryId;
 
@@ -713,9 +352,9 @@ Category.reopenClass({
     }
 
     return data.sortBy("read_restricted");
-  },
+  }
 
-  async asyncSearch(term, opts) {
+  static async asyncSearch(term, opts) {
     opts ||= {};
 
     const data = {
@@ -735,7 +374,364 @@ Category.reopenClass({
     return result["categories"].map((category) =>
       Site.current().updateCategory(category)
     );
-  },
+  }
+
+  permissions = null;
+
+  @on("init")
+  setupGroupsAndPermissions() {
+    const availableGroups = this.available_groups;
+    if (!availableGroups) {
+      return;
+    }
+    this.set("availableGroups", availableGroups);
+
+    const groupPermissions = this.group_permissions;
+
+    if (groupPermissions) {
+      this.set(
+        "permissions",
+        groupPermissions.map((elem) => {
+          availableGroups.removeObject(elem.group_name);
+          return elem;
+        })
+      );
+    }
+  }
+
+  @discourseComputed("required_tag_groups", "minimum_required_tags")
+  minimumRequiredTags() {
+    if (this.required_tag_groups?.length > 0) {
+      // it should require the max between the bare minimum set in the category and the sum of the min_count of the
+      // required_tag_groups
+      return Math.max(
+        this.required_tag_groups.reduce((sum, rtg) => sum + rtg.min_count, 0),
+        this.minimum_required_tags || 0
+      );
+    } else {
+      return this.minimum_required_tags > 0 ? this.minimum_required_tags : null;
+    }
+  }
+
+  @discourseComputed
+  availablePermissions() {
+    return [
+      PermissionType.create({ id: PermissionType.FULL }),
+      PermissionType.create({ id: PermissionType.CREATE_POST }),
+      PermissionType.create({ id: PermissionType.READONLY }),
+    ];
+  }
+
+  @discourseComputed("id")
+  searchContext(id) {
+    return { type: "category", id, category: this };
+  }
+
+  @discourseComputed("parentCategory.ancestors")
+  ancestors(parentAncestors) {
+    return [...(parentAncestors || []), this];
+  }
+
+  @discourseComputed("parentCategory.level")
+  level(parentLevel) {
+    if (!parentLevel) {
+      return parentLevel === 0 ? 1 : 0;
+    } else {
+      return parentLevel + 1;
+    }
+  }
+
+  @discourseComputed("has_children", "subcategories")
+  isParent(hasChildren, subcategories) {
+    return hasChildren || (subcategories && subcategories.length > 0);
+  }
+
+  @discourseComputed("subcategories")
+  isGrandParent(subcategories) {
+    return (
+      subcategories &&
+      subcategories.some(
+        (cat) => cat.subcategories && cat.subcategories.length > 0
+      )
+    );
+  }
+
+  @discourseComputed("notification_level")
+  isMuted(notificationLevel) {
+    return notificationLevel === NotificationLevels.MUTED;
+  }
+
+  @discourseComputed("isMuted", "subcategories")
+  isHidden(isMuted, subcategories) {
+    if (!isMuted) {
+      return false;
+    } else if (!subcategories) {
+      return true;
+    }
+
+    if (subcategories.some((cat) => !cat.isHidden)) {
+      return false;
+    }
+
+    return true;
+  }
+
+  @discourseComputed("isMuted", "subcategories")
+  hasMuted(isMuted, subcategories) {
+    if (isMuted) {
+      return true;
+    } else if (!subcategories) {
+      return false;
+    }
+
+    if (subcategories.some((cat) => cat.hasMuted)) {
+      return true;
+    }
+
+    return false;
+  }
+
+  @discourseComputed("notification_level")
+  notificationLevelString(notificationLevel) {
+    // Get the key from the value
+    const notificationLevelString = Object.keys(NotificationLevels).find(
+      (key) => NotificationLevels[key] === notificationLevel
+    );
+    if (notificationLevelString) {
+      return notificationLevelString.toLowerCase();
+    }
+  }
+
+  @discourseComputed("name")
+  path() {
+    return `/c/${Category.slugFor(this)}/${this.id}`;
+  }
+
+  @discourseComputed("path")
+  url(path) {
+    return getURL(path);
+  }
+
+  @discourseComputed
+  fullSlug() {
+    return Category.slugFor(this).replace(/\//g, "-");
+  }
+
+  @discourseComputed("name")
+  nameLower(name) {
+    return name.toLowerCase();
+  }
+
+  @discourseComputed("url")
+  unreadUrl(url) {
+    return `${url}/l/unread`;
+  }
+
+  @discourseComputed("url")
+  newUrl(url) {
+    return `${url}/l/new`;
+  }
+
+  @discourseComputed("color", "text_color")
+  style(color, textColor) {
+    return `background-color: #${color}; color: #${textColor}`;
+  }
+
+  @discourseComputed("topic_count")
+  moreTopics(topicCount) {
+    return topicCount > (this.num_featured_topics || 2);
+  }
+
+  @discourseComputed("topic_count", "subcategories.[]")
+  totalTopicCount(topicCount, subcategories) {
+    if (subcategories) {
+      subcategories.forEach((subcategory) => {
+        topicCount += subcategory.topic_count;
+      });
+    }
+    return topicCount;
+  }
+
+  @discourseComputed("default_slow_mode_seconds")
+  defaultSlowModeMinutes(seconds) {
+    return seconds ? seconds / 60 : null;
+  }
+
+  @discourseComputed("notification_level")
+  isTracked(notificationLevel) {
+    return notificationLevel >= NotificationLevels.TRACKING;
+  }
+
+  get unreadTopicsCount() {
+    return this.topicTrackingState.countUnread({ categoryId: this.id });
+  }
+
+  get newTopicsCount() {
+    return this.topicTrackingState.countNew({ categoryId: this.id });
+  }
+
+  save() {
+    const id = this.id;
+    const url = id ? `/categories/${id}` : "/categories";
+
+    return ajax(url, {
+      contentType: "application/json",
+      data: JSON.stringify({
+        name: this.name,
+        slug: this.slug,
+        color: this.color,
+        text_color: this.text_color,
+        secure: this.secure,
+        permissions: this._permissionsForUpdate(),
+        auto_close_hours: this.auto_close_hours,
+        auto_close_based_on_last_post: this.get(
+          "auto_close_based_on_last_post"
+        ),
+        default_slow_mode_seconds: this.default_slow_mode_seconds,
+        position: this.position,
+        email_in: this.email_in,
+        email_in_allow_strangers: this.email_in_allow_strangers,
+        mailinglist_mirror: this.mailinglist_mirror,
+        parent_category_id: this.parent_category_id,
+        uploaded_logo_id: this.get("uploaded_logo.id"),
+        uploaded_logo_dark_id: this.get("uploaded_logo_dark.id"),
+        uploaded_background_id: this.get("uploaded_background.id"),
+        uploaded_background_dark_id: this.get("uploaded_background_dark.id"),
+        allow_badges: this.allow_badges,
+        category_setting_attributes: this.category_setting,
+        custom_fields: this.custom_fields,
+        topic_template: this.topic_template,
+        form_template_ids: this.form_template_ids,
+        all_topics_wiki: this.all_topics_wiki,
+        allow_unlimited_owner_edits_on_first_post:
+          this.allow_unlimited_owner_edits_on_first_post,
+        allowed_tags: this.allowed_tags,
+        allowed_tag_groups: this.allowed_tag_groups,
+        allow_global_tags: this.allow_global_tags,
+        required_tag_groups: this.required_tag_groups,
+        sort_order: this.sort_order,
+        sort_ascending: this.sort_ascending,
+        topic_featured_link_allowed: this.topic_featured_link_allowed,
+        show_subcategory_list: this.show_subcategory_list,
+        num_featured_topics: this.num_featured_topics,
+        default_view: this.default_view,
+        subcategory_list_style: this.subcategory_list_style,
+        default_top_period: this.default_top_period,
+        minimum_required_tags: this.minimum_required_tags,
+        navigate_to_first_post_after_read: this.get(
+          "navigate_to_first_post_after_read"
+        ),
+        search_priority: this.search_priority,
+        reviewable_by_group_name: this.reviewable_by_group_name,
+        read_only_banner: this.read_only_banner,
+        default_list_filter: this.default_list_filter,
+      }),
+      type: id ? "PUT" : "POST",
+    });
+  }
+
+  _permissionsForUpdate() {
+    const permissions = this.permissions;
+    let rval = {};
+    if (permissions.length) {
+      permissions.forEach((p) => (rval[p.group_name] = p.permission_type));
+    } else {
+      // empty permissions => staff-only access
+      rval[STAFF_GROUP_NAME] = PermissionType.FULL;
+    }
+    return rval;
+  }
+
+  destroy() {
+    return ajax(`/categories/${this.id || this.slug}`, {
+      type: "DELETE",
+    });
+  }
+
+  addPermission(permission) {
+    this.permissions.addObject(permission);
+    this.availableGroups.removeObject(permission.group_name);
+  }
+
+  removePermission(group_name) {
+    const permission = this.permissions.findBy("group_name", group_name);
+    if (permission) {
+      this.permissions.removeObject(permission);
+      this.availableGroups.addObject(group_name);
+    }
+  }
+
+  updatePermission(group_name, type) {
+    this.permissions.forEach((p, i) => {
+      if (p.group_name === group_name) {
+        this.set(`permissions.${i}.permission_type`, type);
+      }
+    });
+  }
+
+  @discourseComputed("topics")
+  latestTopic(topics) {
+    if (topics && topics.length) {
+      return topics[0];
+    }
+  }
+
+  @discourseComputed("topics")
+  featuredTopics(topics) {
+    if (topics && topics.length) {
+      return topics.slice(0, this.num_featured_topics || 2);
+    }
+  }
+
+  setNotification(notification_level) {
+    User.currentProp(
+      "muted_category_ids",
+      User.current().calculateMutedIds(
+        notification_level,
+        this.id,
+        "muted_category_ids"
+      )
+    );
+
+    const url = `/category/${this.id}/notifications`;
+    return ajax(url, { data: { notification_level }, type: "POST" }).then(
+      (data) => {
+        User.current().set(
+          "indirectly_muted_category_ids",
+          data.indirectly_muted_category_ids
+        );
+        this.set("notification_level", notification_level);
+        this.notifyPropertyChange("notification_level");
+      }
+    );
+  }
+
+  @discourseComputed("id")
+  isUncategorizedCategory(id) {
+    return Category.isUncategorized(id);
+  }
+
+  get canCreateTopic() {
+    return this.permission === PermissionType.FULL;
+  }
+
+  get subcategoryWithCreateTopicPermission() {
+    return this.subcategories?.find(
+      (subcategory) => subcategory.canCreateTopic
+    );
+  }
+}
+
+let _uncategorized;
+
+const categoryMultiCache = new MultiCache(async (ids) => {
+  const result = await ajax("/categories/find", { data: { ids } });
+
+  return new Map(
+    result["categories"].map((category) => [category.id, category])
+  );
 });
 
-export default Category;
+export function resetCategoryCache() {
+  categoryMultiCache.reset();
+}
diff --git a/app/assets/javascripts/discourse/app/models/draft.js b/app/assets/javascripts/discourse/app/models/draft.js
index 4275cab1630..02033f1fc74 100644
--- a/app/assets/javascripts/discourse/app/models/draft.js
+++ b/app/assets/javascripts/discourse/app/models/draft.js
@@ -1,26 +1,24 @@
 import EmberObject from "@ember/object";
 import { ajax } from "discourse/lib/ajax";
 
-const Draft = EmberObject.extend();
-
-Draft.reopenClass({
-  clear(key, sequence) {
+export default class Draft extends EmberObject {
+  static clear(key, sequence) {
     return ajax(`/drafts/${key}.json`, {
       type: "DELETE",
       data: { draft_key: key, sequence },
     });
-  },
+  }
 
-  get(key) {
+  static get(key) {
     return ajax(`/drafts/${key}.json`);
-  },
+  }
 
-  getLocal(key, current) {
+  static getLocal(key, current) {
     // TODO: implement this
     return current;
-  },
+  }
 
-  save(key, sequence, data, clientId, { forceSave = false } = {}) {
+  static save(key, sequence, data, clientId, { forceSave = false } = {}) {
     data = typeof data === "string" ? data : JSON.stringify(data);
     return ajax("/drafts.json", {
       type: "POST",
@@ -33,7 +31,5 @@ Draft.reopenClass({
       },
       ignoreUnsent: false,
     });
-  },
-});
-
-export default Draft;
+  }
+}
diff --git a/app/assets/javascripts/discourse/app/models/group-history.js b/app/assets/javascripts/discourse/app/models/group-history.js
index c13785717c7..c72c7cd6b24 100644
--- a/app/assets/javascripts/discourse/app/models/group-history.js
+++ b/app/assets/javascripts/discourse/app/models/group-history.js
@@ -2,9 +2,9 @@ import RestModel from "discourse/models/rest";
 import discourseComputed from "discourse-common/utils/decorators";
 import I18n from "discourse-i18n";
 
-export default RestModel.extend({
+export default class GroupHistory extends RestModel {
   @discourseComputed("action")
   actionTitle(action) {
     return I18n.t(`group_histories.actions.${action}`);
-  },
-});
+  }
+}
diff --git a/app/assets/javascripts/discourse/app/models/group.js b/app/assets/javascripts/discourse/app/models/group.js
index f1e476ec9ef..580efaad6b0 100644
--- a/app/assets/javascripts/discourse/app/models/group.js
+++ b/app/assets/javascripts/discourse/app/models/group.js
@@ -11,34 +11,56 @@ import Topic from "discourse/models/topic";
 import User from "discourse/models/user";
 import discourseComputed, { observes } from "discourse-common/utils/decorators";
 
-const Group = RestModel.extend({
-  user_count: 0,
-  limit: null,
-  offset: null,
+export default class Group extends RestModel {
+  static findAll(opts) {
+    return ajax("/groups/search.json", { data: opts }).then((groups) =>
+      groups.map((g) => Group.create(g))
+    );
+  }
 
-  request_count: 0,
-  requestersLimit: null,
-  requestersOffset: null,
+  static loadMembers(name, opts) {
+    return ajax(`/groups/${name}/members.json`, { data: opts });
+  }
 
+  static mentionable(name) {
+    return ajax(`/groups/${name}/mentionable`);
+  }
+
+  static messageable(name) {
+    return ajax(`/groups/${name}/messageable`);
+  }
+
+  static checkName(name) {
+    return ajax("/groups/check-name", { data: { group_name: name } });
+  }
+
+  user_count = 0;
+  limit = null;
+  offset = null;
+  request_count = 0;
+  requestersLimit = null;
+  requestersOffset = null;
+
+  @equal("mentionable_level", 99) canEveryoneMention;
   init() {
-    this._super(...arguments);
+    super.init(...arguments);
     this.setProperties({ members: [], requesters: [] });
-  },
+  }
 
   @discourseComputed("automatic_membership_email_domains")
   emailDomains(value) {
     return isEmpty(value) ? "" : value;
-  },
+  }
 
   @discourseComputed("associated_group_ids")
   associatedGroupIds(value) {
     return isEmpty(value) ? [] : value;
-  },
+  }
 
   @discourseComputed("automatic")
   type(automatic) {
     return automatic ? "automatic" : "custom";
-  },
+  }
 
   async reloadMembers(params, refresh) {
     if (isEmpty(this.name) || !this.can_see_members) {
@@ -73,7 +95,7 @@ const Group = RestModel.extend({
       limit: response.meta.limit,
       offset: response.meta.offset,
     });
-  },
+  }
 
   findRequesters(params, refresh) {
     if (isEmpty(this.name) || !this.can_see_members) {
@@ -103,7 +125,7 @@ const Group = RestModel.extend({
         requestersOffset: result.meta.offset,
       });
     });
-  },
+  }
 
   async removeOwner(member) {
     await ajax(`/admin/groups/${this.id}/owners.json`, {
@@ -111,7 +133,7 @@ const Group = RestModel.extend({
       data: { user_id: member.id },
     });
     await this.reloadMembers({}, true);
-  },
+  }
 
   async removeMember(member, params) {
     await ajax(`/groups/${this.id}/members.json`, {
@@ -119,7 +141,7 @@ const Group = RestModel.extend({
       data: { user_id: member.id },
     });
     await this.reloadMembers(params, true);
-  },
+  }
 
   async leave() {
     await ajax(`/groups/${this.id}/leave.json`, {
@@ -127,7 +149,7 @@ const Group = RestModel.extend({
     });
     this.set("can_see_members", this.members_visibility_level < 2);
     await this.reloadMembers({}, true);
-  },
+  }
 
   async addMembers(usernames, filter, notifyUsers, emails = []) {
     const response = await ajax(`/groups/${this.id}/members.json`, {
@@ -139,14 +161,14 @@ const Group = RestModel.extend({
     } else {
       await this.reloadMembers();
     }
-  },
+  }
 
   async join() {
     await ajax(`/groups/${this.id}/join.json`, {
       type: "PUT",
     });
     await this.reloadMembers({}, true);
-  },
+  }
 
   async addOwners(usernames, filter, notifyUsers) {
     const response = await ajax(`/groups/${this.id}/owners.json`, {
@@ -159,44 +181,42 @@ const Group = RestModel.extend({
     } else {
       await this.reloadMembers({}, true);
     }
-  },
+  }
 
   _filterMembers(usernames) {
     return this.reloadMembers({ filter: usernames.join(",") });
-  },
+  }
 
   @discourseComputed("display_name", "name")
   displayName(groupDisplayName, name) {
     return groupDisplayName || name;
-  },
+  }
 
   @discourseComputed("flair_bg_color")
   flairBackgroundHexColor(flairBgColor) {
     return flairBgColor
       ? flairBgColor.replace(new RegExp("[^0-9a-fA-F]", "g"), "")
       : null;
-  },
+  }
 
   @discourseComputed("flair_color")
   flairHexColor(flairColor) {
     return flairColor
       ? flairColor.replace(new RegExp("[^0-9a-fA-F]", "g"), "")
       : null;
-  },
-
-  canEveryoneMention: equal("mentionable_level", 99),
+  }
 
   @discourseComputed("visibility_level")
   isPrivate(visibilityLevel) {
     return visibilityLevel > 1;
-  },
+  }
 
   @observes("isPrivate", "canEveryoneMention")
   _updateAllowMembershipRequests() {
     if (this.isPrivate || !this.canEveryoneMention) {
       this.set("allow_membership_requests", false);
     }
-  },
+  }
 
   @dependentKeyCompat
   get watchingCategories() {
@@ -210,14 +230,14 @@ const Group = RestModel.extend({
     }
 
     return Category.findByIds(this.get("watching_category_ids"));
-  },
+  }
 
   set watchingCategories(categories) {
     this.set(
       "watching_category_ids",
       categories.map((c) => c.id)
     );
-  },
+  }
 
   @dependentKeyCompat
   get trackingCategories() {
@@ -231,14 +251,14 @@ const Group = RestModel.extend({
     }
 
     return Category.findByIds(this.get("tracking_category_ids"));
-  },
+  }
 
   set trackingCategories(categories) {
     this.set(
       "tracking_category_ids",
       categories.map((c) => c.id)
     );
-  },
+  }
 
   @dependentKeyCompat
   get watchingFirstPostCategories() {
@@ -252,14 +272,14 @@ const Group = RestModel.extend({
     }
 
     return Category.findByIds(this.get("watching_first_post_category_ids"));
-  },
+  }
 
   set watchingFirstPostCategories(categories) {
     this.set(
       "watching_first_post_category_ids",
       categories.map((c) => c.id)
     );
-  },
+  }
 
   @dependentKeyCompat
   get regularCategories() {
@@ -273,14 +293,14 @@ const Group = RestModel.extend({
     }
 
     return Category.findByIds(this.get("regular_category_ids"));
-  },
+  }
 
   set regularCategories(categories) {
     this.set(
       "regular_category_ids",
       categories.map((c) => c.id)
     );
-  },
+  }
 
   @dependentKeyCompat
   get mutedCategories() {
@@ -294,14 +314,14 @@ const Group = RestModel.extend({
     }
 
     return Category.findByIds(this.get("muted_category_ids"));
-  },
+  }
 
   set mutedCategories(categories) {
     this.set(
       "muted_category_ids",
       categories.map((c) => c.id)
     );
-  },
+  }
 
   asJSON() {
     const attrs = {
@@ -382,7 +402,7 @@ const Group = RestModel.extend({
     }
 
     return attrs;
-  },
+  }
 
   async create() {
     const response = await ajax("/admin/groups", {
@@ -397,21 +417,21 @@ const Group = RestModel.extend({
     });
 
     await this.reloadMembers();
-  },
+  }
 
   save(opts = {}) {
     return ajax(`/groups/${this.id}`, {
       type: "PUT",
       data: Object.assign({ group: this.asJSON() }, opts),
     });
-  },
+  }
 
   destroy() {
     if (!this.id) {
       return;
     }
     return ajax(`/admin/groups/${this.id}`, { type: "DELETE" });
-  },
+  }
 
   findLogs(offset, filters) {
     return ajax(`/groups/${this.name}/logs.json`, {
@@ -422,7 +442,7 @@ const Group = RestModel.extend({
         all_loaded: results["all_loaded"],
       });
     });
-  },
+  }
 
   findPosts(opts) {
     opts = opts || {};
@@ -445,7 +465,7 @@ const Group = RestModel.extend({
         return EmberObject.create(p);
       });
     });
-  },
+  }
 
   setNotification(notification_level, userId) {
     this.set("group_user.notification_level", notification_level);
@@ -453,38 +473,12 @@ const Group = RestModel.extend({
       data: { notification_level, user_id: userId },
       type: "POST",
     });
-  },
+  }
 
   requestMembership(reason) {
     return ajax(`/groups/${this.name}/request_membership.json`, {
       type: "POST",
       data: { reason },
     });
-  },
-});
-
-Group.reopenClass({
-  findAll(opts) {
-    return ajax("/groups/search.json", { data: opts }).then((groups) =>
-      groups.map((g) => Group.create(g))
-    );
-  },
-
-  loadMembers(name, opts) {
-    return ajax(`/groups/${name}/members.json`, { data: opts });
-  },
-
-  mentionable(name) {
-    return ajax(`/groups/${name}/mentionable`);
-  },
-
-  messageable(name) {
-    return ajax(`/groups/${name}/messageable`);
-  },
-
-  checkName(name) {
-    return ajax("/groups/check-name", { data: { group_name: name } });
-  },
-});
-
-export default Group;
+  }
+}
diff --git a/app/assets/javascripts/discourse/app/models/invite.js b/app/assets/javascripts/discourse/app/models/invite.js
index 2382fe60350..00ffdf8b3d6 100644
--- a/app/assets/javascripts/discourse/app/models/invite.js
+++ b/app/assets/javascripts/discourse/app/models/invite.js
@@ -9,65 +9,16 @@ import Topic from "discourse/models/topic";
 import User from "discourse/models/user";
 import discourseComputed from "discourse-common/utils/decorators";
 
-const Invite = EmberObject.extend({
-  save(data) {
-    const promise = this.id
-      ? ajax(`/invites/${this.id}`, { type: "PUT", data })
-      : ajax("/invites", { type: "POST", data });
-
-    return promise.then((result) => this.setProperties(result));
-  },
-
-  destroy() {
-    return ajax("/invites", {
-      type: "DELETE",
-      data: { id: this.id },
-    }).then(() => this.set("destroyed", true));
-  },
-
-  reinvite() {
-    return ajax("/invites/reinvite", {
-      type: "POST",
-      data: { email: this.email },
-    })
-      .then(() => this.set("reinvited", true))
-      .catch(popupAjaxError);
-  },
-
-  @discourseComputed("invite_key")
-  shortKey(key) {
-    return key.slice(0, 4) + "...";
-  },
-
-  @discourseComputed("groups")
-  groupIds(groups) {
-    return groups ? groups.map((group) => group.id) : [];
-  },
-
-  @discourseComputed("topics.firstObject")
-  topic(topicData) {
-    return topicData ? Topic.create(topicData) : null;
-  },
-
-  @discourseComputed("email", "domain")
-  emailOrDomain(email, domain) {
-    return email || domain;
-  },
-
-  topicId: alias("topics.firstObject.id"),
-  topicTitle: alias("topics.firstObject.title"),
-});
-
-Invite.reopenClass({
-  create() {
-    const result = this._super.apply(this, arguments);
+export default class Invite extends EmberObject {
+  static create() {
+    const result = super.create(...arguments);
     if (result.user) {
       result.user = User.create(result.user);
     }
     return result;
-  },
+  }
 
-  findInvitedBy(user, filter, search, offset) {
+  static findInvitedBy(user, filter, search, offset) {
     if (!user) {
       Promise.resolve();
     }
@@ -87,15 +38,60 @@ Invite.reopenClass({
       result.invites = result.invites.map((i) => Invite.create(i));
       return EmberObject.create(result);
     });
-  },
+  }
 
-  reinviteAll() {
+  static reinviteAll() {
     return ajax("/invites/reinvite-all", { type: "POST" });
-  },
+  }
 
-  destroyAllExpired() {
+  static destroyAllExpired() {
     return ajax("/invites/destroy-all-expired", { type: "POST" });
-  },
-});
+  }
 
-export default Invite;
+  @alias("topics.firstObject.id") topicId;
+  @alias("topics.firstObject.title") topicTitle;
+
+  save(data) {
+    const promise = this.id
+      ? ajax(`/invites/${this.id}`, { type: "PUT", data })
+      : ajax("/invites", { type: "POST", data });
+
+    return promise.then((result) => this.setProperties(result));
+  }
+
+  destroy() {
+    return ajax("/invites", {
+      type: "DELETE",
+      data: { id: this.id },
+    }).then(() => this.set("destroyed", true));
+  }
+
+  reinvite() {
+    return ajax("/invites/reinvite", {
+      type: "POST",
+      data: { email: this.email },
+    })
+      .then(() => this.set("reinvited", true))
+      .catch(popupAjaxError);
+  }
+
+  @discourseComputed("invite_key")
+  shortKey(key) {
+    return key.slice(0, 4) + "...";
+  }
+
+  @discourseComputed("groups")
+  groupIds(groups) {
+    return groups ? groups.map((group) => group.id) : [];
+  }
+
+  @discourseComputed("topics.firstObject")
+  topic(topicData) {
+    return topicData ? Topic.create(topicData) : null;
+  }
+
+  @discourseComputed("email", "domain")
+  emailOrDomain(email, domain) {
+    return email || domain;
+  }
+}
diff --git a/app/assets/javascripts/discourse/app/models/live-post-counts.js b/app/assets/javascripts/discourse/app/models/live-post-counts.js
index bac51ff8250..3dd8baf44c3 100644
--- a/app/assets/javascripts/discourse/app/models/live-post-counts.js
+++ b/app/assets/javascripts/discourse/app/models/live-post-counts.js
@@ -1,14 +1,10 @@
 import EmberObject from "@ember/object";
 import { ajax } from "discourse/lib/ajax";
 
-const LivePostCounts = EmberObject.extend({});
-
-LivePostCounts.reopenClass({
-  find() {
+export default class LivePostCounts extends EmberObject {
+  static find() {
     return ajax("/about/live_post_counts.json").then((result) =>
       LivePostCounts.create(result)
     );
-  },
-});
-
-export default LivePostCounts;
+  }
+}
diff --git a/app/assets/javascripts/discourse/app/models/login-method.js b/app/assets/javascripts/discourse/app/models/login-method.js
index 84bd2d3a071..5da0cb4bc0d 100644
--- a/app/assets/javascripts/discourse/app/models/login-method.js
+++ b/app/assets/javascripts/discourse/app/models/login-method.js
@@ -7,11 +7,31 @@ import getURL from "discourse-common/lib/get-url";
 import discourseComputed from "discourse-common/utils/decorators";
 import I18n from "discourse-i18n";
 
-const LoginMethod = EmberObject.extend({
+export default class LoginMethod extends EmberObject {
+  static buildPostForm(url) {
+    // Login always happens in an anonymous context, with no CSRF token
+    // So we need to fetch it before sending a POST request
+    return updateCsrfToken().then(() => {
+      const form = document.createElement("form");
+      form.setAttribute("style", "display:none;");
+      form.setAttribute("method", "post");
+      form.setAttribute("action", url);
+
+      const input = document.createElement("input");
+      input.setAttribute("name", "authenticity_token");
+      input.setAttribute("value", Session.currentProp("csrfToken"));
+      form.appendChild(input);
+
+      document.body.appendChild(form);
+
+      return form;
+    });
+  }
+
   @discourseComputed
   title() {
     return this.title_override || I18n.t(`login.${this.name}.title`);
-  },
+  }
 
   @discourseComputed
   screenReaderTitle() {
@@ -19,12 +39,12 @@ const LoginMethod = EmberObject.extend({
       this.title_override ||
       I18n.t(`login.${this.name}.sr_title`, { defaultValue: this.title })
     );
-  },
+  }
 
   @discourseComputed
   prettyName() {
     return this.pretty_name_override || I18n.t(`login.${this.name}.name`);
-  },
+  }
 
   doLogin({ reconnect = false, signup = false, params = {} } = {}) {
     if (this.customLogin) {
@@ -56,30 +76,8 @@ const LoginMethod = EmberObject.extend({
     }
 
     return LoginMethod.buildPostForm(authUrl).then((form) => form.submit());
-  },
-});
-
-LoginMethod.reopenClass({
-  buildPostForm(url) {
-    // Login always happens in an anonymous context, with no CSRF token
-    // So we need to fetch it before sending a POST request
-    return updateCsrfToken().then(() => {
-      const form = document.createElement("form");
-      form.setAttribute("style", "display:none;");
-      form.setAttribute("method", "post");
-      form.setAttribute("action", url);
-
-      const input = document.createElement("input");
-      input.setAttribute("name", "authenticity_token");
-      input.setAttribute("value", Session.currentProp("csrfToken"));
-      form.appendChild(input);
-
-      document.body.appendChild(form);
-
-      return form;
-    });
-  },
-});
+  }
+}
 
 let methods;
 
@@ -101,5 +99,3 @@ export function findAll() {
 export function clearAuthMethods() {
   methods = undefined;
 }
-
-export default LoginMethod;
diff --git a/app/assets/javascripts/discourse/app/models/pending-post.js b/app/assets/javascripts/discourse/app/models/pending-post.js
index be0ed7748f8..3df8c2439b0 100644
--- a/app/assets/javascripts/discourse/app/models/pending-post.js
+++ b/app/assets/javascripts/discourse/app/models/pending-post.js
@@ -5,27 +5,27 @@ import RestModel from "discourse/models/rest";
 import discourseComputed from "discourse-common/utils/decorators";
 import Category from "./category";
 
-const PendingPost = RestModel.extend({
-  expandedExcerpt: null,
-  postUrl: reads("topic_url"),
-  truncated: false,
+export default class PendingPost extends RestModel {
+  expandedExcerpt = null;
+
+  @reads("topic_url") postUrl;
+
+  truncated = false;
 
   init() {
-    this._super(...arguments);
+    super.init(...arguments);
     cook(this.raw_text).then((cooked) => {
       this.set("expandedExcerpt", cooked);
     });
-  },
+  }
 
   @discourseComputed("username")
   userUrl(username) {
     return userPath(username.toLowerCase());
-  },
+  }
 
   @discourseComputed("category_id")
   category() {
     return Category.findById(this.category_id);
-  },
-});
-
-export default PendingPost;
+  }
+}
diff --git a/app/assets/javascripts/discourse/app/models/permission-type.js b/app/assets/javascripts/discourse/app/models/permission-type.js
index 90a3727883d..e0fec7e90c2 100644
--- a/app/assets/javascripts/discourse/app/models/permission-type.js
+++ b/app/assets/javascripts/discourse/app/models/permission-type.js
@@ -6,20 +6,18 @@ export function buildPermissionDescription(id) {
   return I18n.t("permission_types." + PermissionType.DESCRIPTION_KEYS[id]);
 }
 
-const PermissionType = EmberObject.extend({
+export default class PermissionType extends EmberObject {
+  static FULL = 1;
+  static CREATE_POST = 2;
+  static READONLY = 3;
+  static DESCRIPTION_KEYS = {
+    1: "full",
+    2: "create_post",
+    3: "readonly",
+  };
+
   @discourseComputed("id")
   description(id) {
     return buildPermissionDescription(id);
-  },
-});
-
-PermissionType.FULL = 1;
-PermissionType.CREATE_POST = 2;
-PermissionType.READONLY = 3;
-PermissionType.DESCRIPTION_KEYS = {
-  1: "full",
-  2: "create_post",
-  3: "readonly",
-};
-
-export default PermissionType;
+  }
+}
diff --git a/app/assets/javascripts/discourse/app/models/post-action-type.js b/app/assets/javascripts/discourse/app/models/post-action-type.js
index 35a93b54c5d..2ab8b85969a 100644
--- a/app/assets/javascripts/discourse/app/models/post-action-type.js
+++ b/app/assets/javascripts/discourse/app/models/post-action-type.js
@@ -3,6 +3,6 @@ import RestModel from "discourse/models/rest";
 
 export const MAX_MESSAGE_LENGTH = 500;
 
-export default RestModel.extend({
-  notCustomFlag: not("is_custom_flag"),
-});
+export default class PostActionType extends RestModel {
+  @not("is_custom_flag") notCustomFlag;
+}
diff --git a/app/assets/javascripts/discourse/app/models/post-stream.js b/app/assets/javascripts/discourse/app/models/post-stream.js
index ce70c6af701..174a013b443 100644
--- a/app/assets/javascripts/discourse/app/models/post-stream.js
+++ b/app/assets/javascripts/discourse/app/models/post-stream.js
@@ -33,23 +33,33 @@ export function resetLastEditNotificationClick() {
   _lastEditNotificationClick = null;
 }
 
-export default RestModel.extend({
-  _identityMap: null,
-  posts: null,
-  stream: null,
-  userFilters: null,
-  loaded: null,
-  loadingAbove: null,
-  loadingBelow: null,
-  loadingFilter: null,
-  loadingNearPost: null,
-  stagingPost: null,
-  postsWithPlaceholders: null,
-  timelineLookup: null,
-  filterRepliesToPostNumber: null,
-  filterUpwardsPostID: null,
-  filter: null,
-  topicSummary: null,
+export default class PostStream extends RestModel {
+  posts = null;
+  stream = null;
+  userFilters = null;
+  loaded = null;
+  loadingAbove = null;
+  loadingBelow = null;
+  loadingFilter = null;
+  loadingNearPost = null;
+  stagingPost = null;
+  postsWithPlaceholders = null;
+  timelineLookup = null;
+  filterRepliesToPostNumber = null;
+  filterUpwardsPostID = null;
+  filter = null;
+  topicSummary = null;
+  lastId = null;
+
+  @or("loadingAbove", "loadingBelow", "loadingFilter", "stagingPost") loading;
+  @not("loading") notLoading;
+  @equal("filter", "summary") summary;
+  @and("notLoading", "hasPosts", "lastPostNotLoaded") canAppendMore;
+  @and("notLoading", "hasPosts", "firstPostNotLoaded") canPrependMore;
+  @not("firstPostPresent") firstPostNotLoaded;
+  @not("loadedAllPosts") lastPostNotLoaded;
+
+  _identityMap = null;
 
   init() {
     this._identityMap = {};
@@ -75,12 +85,7 @@ export default RestModel.extend({
       timelineLookup: [],
       topicSummary: new TopicSummary(),
     });
-  },
-
-  loading: or("loadingAbove", "loadingBelow", "loadingFilter", "stagingPost"),
-  notLoading: not("loading"),
-
-  summary: equal("filter", "summary"),
+  }
 
   @discourseComputed(
     "isMegaTopic",
@@ -89,20 +94,17 @@ export default RestModel.extend({
   )
   filteredPostsCount(isMegaTopic, streamLength, topicHighestPostNumber) {
     return isMegaTopic ? topicHighestPostNumber : streamLength;
-  },
+  }
 
   @discourseComputed("posts.[]")
   hasPosts() {
     return this.get("posts.length") > 0;
-  },
+  }
 
   @discourseComputed("hasPosts", "filteredPostsCount")
   hasLoadedData(hasPosts, filteredPostsCount) {
     return hasPosts && filteredPostsCount > 0;
-  },
-
-  canAppendMore: and("notLoading", "hasPosts", "lastPostNotLoaded"),
-  canPrependMore: and("notLoading", "hasPosts", "firstPostNotLoaded"),
+  }
 
   @discourseComputed("hasLoadedData", "posts.[]")
   firstPostPresent(hasLoadedData) {
@@ -111,16 +113,12 @@ export default RestModel.extend({
     }
 
     return !!this.posts.findBy("post_number", 1);
-  },
-
-  firstPostNotLoaded: not("firstPostPresent"),
-
-  lastId: null,
+  }
 
   @discourseComputed("isMegaTopic", "stream.lastObject", "lastId")
   lastPostId(isMegaTopic, streamLastId, lastId) {
     return isMegaTopic ? lastId : streamLastId;
-  },
+  }
 
   @discourseComputed("hasLoadedData", "lastPostId", "posts.@each.id")
   loadedAllPosts(hasLoadedData, lastPostId) {
@@ -132,9 +130,7 @@ export default RestModel.extend({
     }
 
     return !!this.posts.findBy("id", lastPostId);
-  },
-
-  lastPostNotLoaded: not("loadedAllPosts"),
+  }
 
   /**
     Returns a JS Object of current stream filter options. It should match the query
@@ -167,7 +163,7 @@ export default RestModel.extend({
     }
 
     return result;
-  },
+  }
 
   @discourseComputed("streamFilters.[]", "topic.posts_count", "posts.length")
   hasNoFilters() {
@@ -176,7 +172,7 @@ export default RestModel.extend({
       streamFilters &&
       (streamFilters.filter === "summary" || streamFilters.username_filters)
     );
-  },
+  }
 
   /**
     Returns the window of posts above the current set in the stream, bound to the top of the stream.
@@ -206,7 +202,7 @@ export default RestModel.extend({
       startIndex = 0;
     }
     return stream.slice(startIndex, firstIndex);
-  },
+  }
 
   /**
     Returns the window of posts below the current set in the stream, bound by the bottom of the
@@ -234,7 +230,7 @@ export default RestModel.extend({
       lastIndex + 1,
       lastIndex + this.get("topic.chunk_size") + 1
     );
-  },
+  }
 
   cancelFilter() {
     this.setProperties({
@@ -244,7 +240,7 @@ export default RestModel.extend({
       mixedHiddenPosts: false,
       filter: null,
     });
-  },
+  }
 
   refreshAndJumpToSecondVisible() {
     return this.refresh({}).then(() => {
@@ -252,20 +248,20 @@ export default RestModel.extend({
         DiscourseURL.jumpToPost(this.posts[1].get("post_number"));
       }
     });
-  },
+  }
 
   showTopReplies() {
     this.cancelFilter();
     this.set("filter", "summary");
     return this.refreshAndJumpToSecondVisible();
-  },
+  }
 
   // Filter the stream to a particular user.
   filterParticipant(username) {
     this.cancelFilter();
     this.userFilters.addObject(username);
     return this.refreshAndJumpToSecondVisible();
-  },
+  }
 
   filterReplies(postNumber, postId) {
     this.cancelFilter();
@@ -295,7 +291,7 @@ export default RestModel.extend({
         highlightPost(postNumber);
       });
     });
-  },
+  }
 
   filterUpwards(postID) {
     this.cancelFilter();
@@ -316,7 +312,7 @@ export default RestModel.extend({
         });
       }
     });
-  },
+  }
 
   /**
     Loads a new set of posts into the stream. If you provide a `nearPost` option and the post
@@ -378,7 +374,7 @@ export default RestModel.extend({
       .finally(() => {
         this.set("loadingNearPost", null);
       });
-  },
+  }
 
   // Fill in a gap of posts before a particular post
   fillGapBefore(post, gap) {
@@ -420,7 +416,7 @@ export default RestModel.extend({
       }
     }
     return Promise.resolve();
-  },
+  }
 
   // Fill in a gap of posts after a particular post
   fillGapAfter(post, gap) {
@@ -436,7 +432,7 @@ export default RestModel.extend({
       });
     }
     return Promise.resolve();
-  },
+  }
 
   gapExpanded() {
     this.appEvents.trigger("post-stream:refresh");
@@ -446,7 +442,7 @@ export default RestModel.extend({
     if (this.streamFilters && this.streamFilters.replies_to_post_number) {
       this.set("streamFilters.mixedHiddenPosts", true);
     }
-  },
+  }
 
   // Appends the next window of posts to the stream. Call it when scrolling downwards.
   appendMore() {
@@ -493,7 +489,7 @@ export default RestModel.extend({
           this.set("loadingBelow", false);
         });
     }
-  },
+  }
 
   // Prepend the previous window of posts to the stream. Call it when scrolling upwards.
   prependMore() {
@@ -535,7 +531,7 @@ export default RestModel.extend({
           this.set("loadingAbove", false);
         });
     }
-  },
+  }
 
   /**
     Stage a post for insertion in the stream. It should be rendered right away under the
@@ -573,7 +569,7 @@ export default RestModel.extend({
     }
 
     return "offScreen";
-  },
+  }
 
   // Commit the post we staged. Call this after a save succeeds.
   commitPost(post) {
@@ -587,7 +583,7 @@ export default RestModel.extend({
     this.stream.removeObject(-1);
     this._identityMap[-1] = null;
     this.set("stagingPost", false);
-  },
+  }
 
   /**
     Undo a post we've staged in the stream. Remove it from being rendered and revert the
@@ -607,7 +603,7 @@ export default RestModel.extend({
     });
 
     // TODO unfudge reply count on parent post
-  },
+  }
 
   prependPost(post) {
     this._initUserModels(post);
@@ -618,7 +614,7 @@ export default RestModel.extend({
     }
 
     return post;
-  },
+  }
 
   appendPost(post) {
     this._initUserModels(post);
@@ -639,7 +635,7 @@ export default RestModel.extend({
       }
     }
     return post;
-  },
+  }
 
   removePosts(posts) {
     if (isEmpty(posts)) {
@@ -655,12 +651,12 @@ export default RestModel.extend({
       allPosts.removeObjects(posts);
       postIds.forEach((id) => delete identityMap[id]);
     });
-  },
+  }
 
   // Returns a post from the identity map if it's been inserted.
   findLoadedPost(id) {
     return this._identityMap[id];
-  },
+  }
 
   loadPostByPostNumber(postNumber) {
     const url = `/posts/by_number/${this.get("topic.id")}/${postNumber}`;
@@ -669,7 +665,7 @@ export default RestModel.extend({
     return ajax(url).then((post) => {
       return this.storePost(store.createRecord("post", post));
     });
-  },
+  }
 
   loadNearestPostToDate(date) {
     const url = `/posts/by-date/${this.get("topic.id")}/${date}`;
@@ -678,7 +674,7 @@ export default RestModel.extend({
     return ajax(url).then((post) => {
       return this.storePost(store.createRecord("post", post));
     });
-  },
+  }
 
   loadPost(postId) {
     const url = "/posts/" + postId;
@@ -692,7 +688,7 @@ export default RestModel.extend({
 
       return this.storePost(store.createRecord("post", p));
     });
-  },
+  }
 
   /* mainly for backwards compatibility with plugins, used in quick messages plugin
    * TODO: remove July 2022
@@ -705,7 +701,7 @@ export default RestModel.extend({
       }
     );
     return this.triggerNewPostsInStream([postId], opts);
-  },
+  }
 
   /**
     Finds and adds posts to the stream by id. Typically this would happen if we receive a message
@@ -768,7 +764,7 @@ export default RestModel.extend({
     }
 
     return resolved;
-  },
+  }
 
   triggerRecoveredPost(postId) {
     const existing = this._identityMap[postId];
@@ -814,7 +810,7 @@ export default RestModel.extend({
         }
       });
     }
-  },
+  }
 
   triggerDeletedPost(postId) {
     const existing = this._identityMap[postId];
@@ -832,13 +828,13 @@ export default RestModel.extend({
         });
     }
     return Promise.resolve();
-  },
+  }
 
   triggerDestroyedPost(postId) {
     const existing = this._identityMap[postId];
     this.removePosts([existing]);
     return Promise.resolve();
-  },
+  }
 
   triggerChangedPost(postId, updatedAt, opts) {
     opts = opts || {};
@@ -861,7 +857,7 @@ export default RestModel.extend({
       });
     }
     return resolved;
-  },
+  }
 
   triggerLikedPost(postId, likesCount, userID, eventType) {
     const resolved = Promise.resolve();
@@ -873,7 +869,7 @@ export default RestModel.extend({
     }
 
     return resolved;
-  },
+  }
 
   triggerReadPost(postId, readersCount) {
     const resolved = Promise.resolve();
@@ -886,7 +882,7 @@ export default RestModel.extend({
     });
 
     return resolved;
-  },
+  }
 
   triggerChangedTopicStats() {
     if (this.firstPostNotLoaded) {
@@ -897,7 +893,7 @@ export default RestModel.extend({
       const firstPost = this.posts.findBy("post_number", 1);
       return firstPost.id;
     });
-  },
+  }
 
   postForPostNumber(postNumber) {
     if (!this.hasPosts) {
@@ -907,7 +903,7 @@ export default RestModel.extend({
     return this.posts.find((p) => {
       return p.get("post_number") === postNumber;
     });
-  },
+  }
 
   /**
     Returns the closest post given a postNumber that may not exist in the stream.
@@ -935,12 +931,12 @@ export default RestModel.extend({
     });
 
     return closest;
-  },
+  }
 
   // Get the index of a post in the stream. (Use this for the topic progress bar.)
   progressIndexOfPost(post) {
     return this.progressIndexOfPostId(post);
-  },
+  }
 
   // Get the index in the stream of a post id. (Use this for the topic progress bar.)
   progressIndexOfPostId(post) {
@@ -952,7 +948,7 @@ export default RestModel.extend({
       const index = this.stream.indexOf(postId);
       return index + 1;
     }
-  },
+  }
 
   /**
     Returns the closest post number given a postNumber that may not exist in the stream.
@@ -982,7 +978,7 @@ export default RestModel.extend({
     });
 
     return closest;
-  },
+  }
 
   closestDaysAgoFor(postNumber) {
     const timelineLookup = this.timelineLookup || [];
@@ -1007,7 +1003,7 @@ export default RestModel.extend({
     if (val) {
       return val[1];
     }
-  },
+  }
 
   // Find a postId for a postNumber, respecting gaps
   findPostIdForPostNumber(postNumber) {
@@ -1037,7 +1033,7 @@ export default RestModel.extend({
       }
       sum++;
     }
-  },
+  }
 
   updateFromJson(postStreamData) {
     const posts = this.posts;
@@ -1057,7 +1053,7 @@ export default RestModel.extend({
       // Update our attributes
       this.setProperties(postStreamData);
     }
-  },
+  }
 
   /**
     Stores a post in our identity map, and sets up the references it needs to
@@ -1094,7 +1090,7 @@ export default RestModel.extend({
       this._identityMap[post.get("id")] = post;
     }
     return post;
-  },
+  }
 
   fetchNextWindow(postNumber, asc, callback) {
     let includeSuggested = !this.get("topic.suggested_topics");
@@ -1124,7 +1120,7 @@ export default RestModel.extend({
         });
       }
     });
-  },
+  }
 
   findPostsByIds(postIds, opts) {
     const identityMap = this._identityMap;
@@ -1134,7 +1130,7 @@ export default RestModel.extend({
     return this.loadIntoIdentityMap(unloaded, opts).then(() => {
       return postIds.map((p) => identityMap[p]).compact();
     });
-  },
+  }
 
   loadIntoIdentityMap(postIds, opts) {
     if (isEmpty(postIds)) {
@@ -1164,7 +1160,7 @@ export default RestModel.extend({
         posts.forEach((p) => this.storePost(store.createRecord("post", p)));
       }
     });
-  },
+  }
 
   backfillExcerpts(streamPosition) {
     this._excerpts = this._excerpts || [];
@@ -1211,7 +1207,7 @@ export default RestModel.extend({
       });
 
     return this._excerpts.loading;
-  },
+  }
 
   excerpt(streamPosition) {
     if (this.isMegaTopic) {
@@ -1234,11 +1230,11 @@ export default RestModel.extend({
         })
         .catch((e) => reject(e));
     });
-  },
+  }
 
   indexOf(post) {
     return this.stream.indexOf(post.get("id"));
-  },
+  }
 
   // Handles an error loading a topic based on a HTTP status code. Updates
   // the text to the correct values.
@@ -1259,19 +1255,19 @@ export default RestModel.extend({
       topic.set("errorMessage", I18n.t("topic.server_error.description"));
       topic.set("noRetry", error.jqXHR.status === 403);
     }
-  },
+  }
 
   collapseSummary() {
     this.topicSummary.collapse();
-  },
+  }
 
   showSummary(currentUser) {
     this.topicSummary.generateSummary(currentUser, this.get("topic.id"));
-  },
+  }
 
   processSummaryUpdate(update) {
     this.topicSummary.processUpdate(update);
-  },
+  }
 
   _initUserModels(post) {
     post.user = User.create({
@@ -1286,7 +1282,7 @@ export default RestModel.extend({
     if (post.mentioned_users) {
       post.mentioned_users = post.mentioned_users.map((u) => User.create(u));
     }
-  },
+  }
 
   _checkIfShouldShowRevisions() {
     if (_lastEditNotificationClick) {
@@ -1306,7 +1302,7 @@ export default RestModel.extend({
         });
       }
     }
-  },
+  }
 
   _setSuggestedTopics(result) {
     if (!result.suggested_topics) {
@@ -1321,5 +1317,5 @@ export default RestModel.extend({
     if (this.topic.isPrivateMessage) {
       this.pmTopicTrackingState.startTracking();
     }
-  },
-});
+  }
+}
diff --git a/app/assets/javascripts/discourse/app/models/published-page.js b/app/assets/javascripts/discourse/app/models/published-page.js
index cdd36bb9de3..099dd2cd02f 100644
--- a/app/assets/javascripts/discourse/app/models/published-page.js
+++ b/app/assets/javascripts/discourse/app/models/published-page.js
@@ -2,8 +2,9 @@ import { computed } from "@ember/object";
 import RestModel from "discourse/models/rest";
 import { getAbsoluteURL } from "discourse-common/lib/get-url";
 
-export default RestModel.extend({
-  url: computed("slug", function () {
+export default class PublishedPage extends RestModel {
+  @computed("slug")
+  get url() {
     return getAbsoluteURL(`/pub/${this.slug}`);
-  }),
-});
+  }
+}
diff --git a/app/assets/javascripts/discourse/app/models/result-set.js b/app/assets/javascripts/discourse/app/models/result-set.js
index 644e75638bc..a3847eaf27f 100644
--- a/app/assets/javascripts/discourse/app/models/result-set.js
+++ b/app/assets/javascripts/discourse/app/models/result-set.js
@@ -2,24 +2,23 @@ import ArrayProxy from "@ember/array/proxy";
 import { Promise } from "rsvp";
 import discourseComputed from "discourse-common/utils/decorators";
 
-export default ArrayProxy.extend({
-  loading: false,
-  loadingMore: false,
-  totalRows: 0,
-  refreshing: false,
-
-  content: null,
-  loadMoreUrl: null,
-  refreshUrl: null,
-  findArgs: null,
-  store: null,
-  __type: null,
-  resultSetMeta: null,
+export default class ResultSet extends ArrayProxy {
+  loading = false;
+  loadingMore = false;
+  totalRows = 0;
+  refreshing = false;
+  content = null;
+  loadMoreUrl = null;
+  refreshUrl = null;
+  findArgs = null;
+  store = null;
+  resultSetMeta = null;
+  __type = null;
 
   @discourseComputed("totalRows", "length")
   canLoadMore(totalRows, length) {
     return length < totalRows;
-  },
+  }
 
   loadMore() {
     const loadMoreUrl = this.loadMoreUrl;
@@ -37,7 +36,7 @@ export default ArrayProxy.extend({
     }
 
     return Promise.resolve();
-  },
+  }
 
   refresh() {
     if (this.refreshing) {
@@ -53,5 +52,5 @@ export default ArrayProxy.extend({
     return this.store
       .refreshResults(this, this.__type, refreshUrl)
       .finally(() => this.set("refreshing", false));
-  },
-});
+  }
+}
diff --git a/app/assets/javascripts/discourse/app/models/reviewable-history.js b/app/assets/javascripts/discourse/app/models/reviewable-history.js
index bb143b712c9..0fac81c219f 100644
--- a/app/assets/javascripts/discourse/app/models/reviewable-history.js
+++ b/app/assets/javascripts/discourse/app/models/reviewable-history.js
@@ -5,6 +5,6 @@ export const CREATED = 0;
 export const TRANSITIONED_TO = 1;
 export const EDITED = 2;
 
-export default RestModel.extend({
-  created: equal("reviewable_history_type", CREATED),
-});
+export default class ReviewableHistory extends RestModel {
+  @equal("reviewable_history_type", CREATED) created;
+}
diff --git a/app/assets/javascripts/discourse/app/models/reviewable.js b/app/assets/javascripts/discourse/app/models/reviewable.js
index a83f6d1d4f8..4c348d5d280 100644
--- a/app/assets/javascripts/discourse/app/models/reviewable.js
+++ b/app/assets/javascripts/discourse/app/models/reviewable.js
@@ -12,7 +12,13 @@ export const REJECTED = 2;
 export const IGNORED = 3;
 export const DELETED = 4;
 
-const Reviewable = RestModel.extend({
+export default class Reviewable extends RestModel {
+  static munge(json) {
+    // ensure we are not overriding category computed property
+    delete json.category;
+    return json;
+  }
+
   @discourseComputed("type", "topic")
   resolvedType(type, topic) {
     // Display "Queued Topic" if the post will create a topic
@@ -21,26 +27,26 @@ const Reviewable = RestModel.extend({
     }
 
     return type;
-  },
+  }
 
   @discourseComputed("resolvedType")
   humanType(resolvedType) {
     return I18n.t(`review.types.${underscore(resolvedType)}.title`, {
       defaultValue: "",
     });
-  },
+  }
 
   @discourseComputed("humanType")
   humanTypeCssClass(humanType) {
     return "-" + dasherize(humanType);
-  },
+  }
 
   @discourseComputed("resolvedType")
   humanNoun(resolvedType) {
     return I18n.t(`review.types.${underscore(resolvedType)}.noun`, {
       defaultValue: "reviewable",
     });
-  },
+  }
 
   @discourseComputed("humanNoun")
   flaggedReviewableContextQuestion(humanNoun) {
@@ -66,12 +72,12 @@ const Reviewable = RestModel.extend({
       reviewable_human_score_types: listOfQuestions,
       reviewable_type: humanNoun,
     });
-  },
+  }
 
   @discourseComputed("category_id")
   category() {
     return Category.findById(this.category_id);
-  },
+  }
 
   update(updates) {
     // If no changes, do nothing
@@ -92,15 +98,5 @@ const Reviewable = RestModel.extend({
 
       this.setProperties(updated);
     });
-  },
-});
-
-Reviewable.reopenClass({
-  munge(json) {
-    // ensure we are not overriding category computed property
-    delete json.category;
-    return json;
-  },
-});
-
-export default Reviewable;
+  }
+}
diff --git a/app/assets/javascripts/discourse/app/models/session.js b/app/assets/javascripts/discourse/app/models/session.js
index f47f0da4a4e..d684efabe89 100644
--- a/app/assets/javascripts/discourse/app/models/session.js
+++ b/app/assets/javascripts/discourse/app/models/session.js
@@ -3,14 +3,10 @@ import RestModel from "discourse/models/rest";
 
 // A data model representing current session data. You can put transient
 // data here you might want later. It is not stored or serialized anywhere.
-const Session = RestModel.extend({
-  hasFocus: null,
+export default class Session extends RestModel.extend().reopenClass(Singleton) {
+  hasFocus = null;
 
   init() {
     this.set("highestSeenByTopic", {});
-  },
-});
-
-Session.reopenClass(Singleton);
-
-export default Session;
+  }
+}
diff --git a/app/assets/javascripts/discourse/app/models/site.js b/app/assets/javascripts/discourse/app/models/site.js
index 5b2c525269e..a6ae21dc1d5 100644
--- a/app/assets/javascripts/discourse/app/models/site.js
+++ b/app/assets/javascripts/discourse/app/models/site.js
@@ -13,149 +13,17 @@ import deprecated from "discourse-common/lib/deprecated";
 import { getOwnerWithFallback } from "discourse-common/lib/get-owner";
 import discourseComputed from "discourse-common/utils/decorators";
 
-const Site = RestModel.extend({
-  isReadOnly: alias("is_readonly"),
-
-  init() {
-    this._super(...arguments);
-
-    this.topicCountDesc = ["topic_count:desc"];
-    this.categories = this.categories || [];
-  },
-
-  @discourseComputed("notification_types")
-  notificationLookup(notificationTypes) {
-    const result = [];
-    Object.keys(notificationTypes).forEach(
-      (k) => (result[notificationTypes[k]] = k)
-    );
-    return result;
-  },
-
-  @discourseComputed("post_action_types.[]")
-  flagTypes() {
-    const postActionTypes = this.post_action_types;
-    if (!postActionTypes) {
-      return [];
-    }
-    return postActionTypes.filterBy("is_flag", true);
-  },
-
-  categoriesByCount: sort("categories", "topicCountDesc"),
-
-  collectUserFields(fields) {
-    fields = fields || {};
-
-    let siteFields = this.user_fields;
-
-    if (!isEmpty(siteFields)) {
-      return siteFields.map((f) => {
-        let value = fields ? fields[f.id.toString()] : null;
-        value = value || htmlSafe("&mdash;");
-        return { name: f.name, value };
-      });
-    }
-    return [];
-  },
-
-  // Sort subcategories under parents
-  @discourseComputed("categoriesByCount", "categories.[]")
-  sortedCategories(categories) {
-    return Category.sortCategories(categories);
-  },
-
-  // Returns it in the correct order, by setting
-  @discourseComputed("categories.[]")
-  categoriesList(categories) {
-    return this.siteSettings.fixed_category_positions
-      ? categories
-      : this.sortedCategories;
-  },
-
-  @discourseComputed("categories.[]", "categories.@each.notification_level")
-  trackedCategoriesList(categories) {
-    const trackedCategories = [];
-
-    for (const category of categories) {
-      if (category.isTracked) {
-        if (
-          this.siteSettings.allow_uncategorized_topics ||
-          !category.isUncategorizedCategory
-        ) {
-          trackedCategories.push(category);
-        }
-      }
-    }
-
-    return trackedCategories;
-  },
-
-  postActionTypeById(id) {
-    return this.get("postActionByIdLookup.action" + id);
-  },
-
-  topicFlagTypeById(id) {
-    return this.get("topicFlagByIdLookup.action" + id);
-  },
-
-  removeCategory(id) {
-    const categories = this.categories;
-    const existingCategory = categories.findBy("id", id);
-    if (existingCategory) {
-      categories.removeObject(existingCategory);
-      delete this.categoriesById.categoryId;
-    }
-  },
-
-  updateCategory(newCategory) {
-    const categories = this.categories;
-    const categoryId = get(newCategory, "id");
-    const existingCategory = categories.findBy("id", categoryId);
-
-    // Don't update null permissions
-    if (newCategory.permission === null) {
-      delete newCategory.permission;
-    }
-
-    if (existingCategory) {
-      existingCategory.setProperties(newCategory);
-      return existingCategory;
-    } else {
-      // TODO insert in right order?
-      newCategory = this.store.createRecord("category", newCategory);
-      categories.pushObject(newCategory);
-      this.categoriesById[categoryId] = newCategory;
-      newCategory.set(
-        "parentCategory",
-        this.categoriesById[newCategory.parent_category_id]
-      );
-      newCategory.set(
-        "subcategories",
-        this.categories.filterBy("parent_category_id", categoryId)
-      );
-      if (newCategory.parentCategory) {
-        if (!newCategory.parentCategory.subcategories) {
-          newCategory.parentCategory.set("subcategories", []);
-        }
-        newCategory.parentCategory.subcategories.pushObject(newCategory);
-      }
-      return newCategory;
-    }
-  },
-});
-
-Site.reopenClass(Singleton, {
-  // The current singleton will retrieve its attributes from the `PreloadStore`.
-  createCurrent() {
+export default class Site extends RestModel.extend().reopenClass(Singleton) {
+  static createCurrent() {
     const store = getOwnerWithFallback(this).lookup("service:store");
     const siteAttributes = PreloadStore.get("site");
     siteAttributes["isReadOnly"] = PreloadStore.get("isReadOnly");
     siteAttributes["isStaffWritesOnly"] = PreloadStore.get("isStaffWritesOnly");
     return store.createRecord("site", siteAttributes);
-  },
+  }
 
-  create() {
-    const result = this._super.apply(this, arguments);
+  static create() {
+    const result = super.create.apply(this, arguments);
     const store = result.store;
 
     if (result.categories) {
@@ -233,8 +101,136 @@ Site.reopenClass(Singleton, {
     }
 
     return result;
-  },
-});
+  }
+
+  @alias("is_readonly") isReadOnly;
+
+  @sort("categories", "topicCountDesc") categoriesByCount;
+  init() {
+    super.init(...arguments);
+
+    this.topicCountDesc = ["topic_count:desc"];
+    this.categories = this.categories || [];
+  }
+
+  @discourseComputed("notification_types")
+  notificationLookup(notificationTypes) {
+    const result = [];
+    Object.keys(notificationTypes).forEach(
+      (k) => (result[notificationTypes[k]] = k)
+    );
+    return result;
+  }
+
+  @discourseComputed("post_action_types.[]")
+  flagTypes() {
+    const postActionTypes = this.post_action_types;
+    if (!postActionTypes) {
+      return [];
+    }
+    return postActionTypes.filterBy("is_flag", true);
+  }
+
+  collectUserFields(fields) {
+    fields = fields || {};
+
+    let siteFields = this.user_fields;
+
+    if (!isEmpty(siteFields)) {
+      return siteFields.map((f) => {
+        let value = fields ? fields[f.id.toString()] : null;
+        value = value || htmlSafe("&mdash;");
+        return { name: f.name, value };
+      });
+    }
+    return [];
+  }
+
+  // Sort subcategories under parents
+  @discourseComputed("categoriesByCount", "categories.[]")
+  sortedCategories(categories) {
+    return Category.sortCategories(categories);
+  }
+
+  // Returns it in the correct order, by setting
+  @discourseComputed("categories.[]")
+  categoriesList(categories) {
+    return this.siteSettings.fixed_category_positions
+      ? categories
+      : this.sortedCategories;
+  }
+
+  @discourseComputed("categories.[]", "categories.@each.notification_level")
+  trackedCategoriesList(categories) {
+    const trackedCategories = [];
+
+    for (const category of categories) {
+      if (category.isTracked) {
+        if (
+          this.siteSettings.allow_uncategorized_topics ||
+          !category.isUncategorizedCategory
+        ) {
+          trackedCategories.push(category);
+        }
+      }
+    }
+
+    return trackedCategories;
+  }
+
+  postActionTypeById(id) {
+    return this.get("postActionByIdLookup.action" + id);
+  }
+
+  topicFlagTypeById(id) {
+    return this.get("topicFlagByIdLookup.action" + id);
+  }
+
+  removeCategory(id) {
+    const categories = this.categories;
+    const existingCategory = categories.findBy("id", id);
+    if (existingCategory) {
+      categories.removeObject(existingCategory);
+      delete this.categoriesById.categoryId;
+    }
+  }
+
+  updateCategory(newCategory) {
+    const categories = this.categories;
+    const categoryId = get(newCategory, "id");
+    const existingCategory = categories.findBy("id", categoryId);
+
+    // Don't update null permissions
+    if (newCategory.permission === null) {
+      delete newCategory.permission;
+    }
+
+    if (existingCategory) {
+      existingCategory.setProperties(newCategory);
+      return existingCategory;
+    } else {
+      // TODO insert in right order?
+      newCategory = this.store.createRecord("category", newCategory);
+      categories.pushObject(newCategory);
+      this.categoriesById[categoryId] = newCategory;
+      newCategory.set(
+        "parentCategory",
+        this.categoriesById[newCategory.parent_category_id]
+      );
+      newCategory.set(
+        "subcategories",
+        this.categories.filterBy("parent_category_id", categoryId)
+      );
+      if (newCategory.parentCategory) {
+        if (!newCategory.parentCategory.subcategories) {
+          newCategory.parentCategory.set("subcategories", []);
+        }
+        newCategory.parentCategory.subcategories.pushObject(newCategory);
+      }
+      return newCategory;
+    }
+  }
+}
 
 if (typeof Discourse !== "undefined") {
   let warned = false;
@@ -252,5 +248,3 @@ if (typeof Discourse !== "undefined") {
     },
   });
 }
-
-export default Site;
diff --git a/app/assets/javascripts/discourse/app/models/static-page.js b/app/assets/javascripts/discourse/app/models/static-page.js
index 230cba23044..60644c690b9 100644
--- a/app/assets/javascripts/discourse/app/models/static-page.js
+++ b/app/assets/javascripts/discourse/app/models/static-page.js
@@ -3,10 +3,8 @@ import $ from "jquery";
 import { Promise } from "rsvp";
 import { ajax } from "discourse/lib/ajax";
 
-const StaticPage = EmberObject.extend();
-
-StaticPage.reopenClass({
-  find(path) {
+export default class StaticPage extends EmberObject {
+  static find(path) {
     return new Promise((resolve) => {
       // Models shouldn't really be doing Ajax request, but this is a huge speed boost if we
       // preload content.
@@ -23,7 +21,5 @@ StaticPage.reopenClass({
         );
       }
     });
-  },
-});
-
-export default StaticPage;
+  }
+}
diff --git a/app/assets/javascripts/discourse/app/models/tag-group.js b/app/assets/javascripts/discourse/app/models/tag-group.js
index e34e5cae711..64d6412a918 100644
--- a/app/assets/javascripts/discourse/app/models/tag-group.js
+++ b/app/assets/javascripts/discourse/app/models/tag-group.js
@@ -2,7 +2,7 @@ import PermissionType from "discourse/models/permission-type";
 import RestModel from "discourse/models/rest";
 import discourseComputed from "discourse-common/utils/decorators";
 
-export default RestModel.extend({
+export default class TagGroup extends RestModel {
   @discourseComputed("permissions")
   permissionName(permissions) {
     if (!permissions) {
@@ -16,5 +16,5 @@ export default RestModel.extend({
     } else {
       return "private";
     }
-  },
-});
+  }
+}
diff --git a/app/assets/javascripts/discourse/app/models/tag.js b/app/assets/javascripts/discourse/app/models/tag.js
index 0de4528e07b..9d9e72443b6 100644
--- a/app/assets/javascripts/discourse/app/models/tag.js
+++ b/app/assets/javascripts/discourse/app/models/tag.js
@@ -2,16 +2,16 @@ import { readOnly } from "@ember/object/computed";
 import RestModel from "discourse/models/rest";
 import discourseComputed from "discourse-common/utils/decorators";
 
-export default RestModel.extend({
-  pmOnly: readOnly("pm_only"),
+export default class Tag extends RestModel {
+  @readOnly("pm_only") pmOnly;
 
   @discourseComputed("count", "pm_count")
   totalCount(count, pmCount) {
     return pmCount ? count + pmCount : count;
-  },
+  }
 
   @discourseComputed("id")
   searchContext(id) {
     return { type: "tag", id, tag: this, name: id };
-  },
-});
+  }
+}
diff --git a/app/assets/javascripts/discourse/app/models/topic-details.js b/app/assets/javascripts/discourse/app/models/topic-details.js
index 2d7096e21e4..509c906042b 100644
--- a/app/assets/javascripts/discourse/app/models/topic-details.js
+++ b/app/assets/javascripts/discourse/app/models/topic-details.js
@@ -8,10 +8,10 @@ import RestModel from "discourse/models/rest";
   When showing topics in lists and such this information should not be required.
 **/
 
-const TopicDetails = RestModel.extend({
-  store: service(),
+export default class TopicDetails extends RestModel {
+  @service store;
 
-  loaded: false,
+  loaded = false;
 
   updateFromJson(details) {
     const topic = this.topic;
@@ -31,7 +31,7 @@ const TopicDetails = RestModel.extend({
 
     this.setProperties(details);
     this.set("loaded", true);
-  },
+  }
 
   updateNotifications(level) {
     return ajax(`/t/${this.get("topic.id")}/notifications`, {
@@ -43,7 +43,7 @@ const TopicDetails = RestModel.extend({
         notifications_reason_id: null,
       });
     });
-  },
+  }
 
   removeAllowedGroup(group) {
     const groups = this.allowed_groups;
@@ -55,7 +55,7 @@ const TopicDetails = RestModel.extend({
     }).then(() => {
       groups.removeObject(groups.findBy("name", name));
     });
-  },
+  }
 
   removeAllowedUser(user) {
     const users = this.allowed_users;
@@ -67,7 +67,5 @@ const TopicDetails = RestModel.extend({
     }).then(() => {
       users.removeObject(users.findBy("username", username));
     });
-  },
-});
-
-export default TopicDetails;
+  }
+}
diff --git a/app/assets/javascripts/discourse/app/models/topic-list.js b/app/assets/javascripts/discourse/app/models/topic-list.js
index 93ca8a55f9d..7a54c8ac3a7 100644
--- a/app/assets/javascripts/discourse/app/models/topic-list.js
+++ b/app/assets/javascripts/discourse/app/models/topic-list.js
@@ -40,9 +40,88 @@ function displayCategoryInList(site, category) {
   return true;
 }
 
-const TopicList = RestModel.extend({
-  session: service(),
-  canLoadMore: notEmpty("more_topics_url"),
+export default class TopicList extends RestModel {
+  static topicsFrom(store, result, opts) {
+    if (!result) {
+      return;
+    }
+
+    opts = opts || {};
+    let listKey = opts.listKey || "topics";
+
+    // Stitch together our side loaded data
+
+    const users = extractByKey(result.users, User);
+    const groups = extractByKey(result.primary_groups, EmberObject);
+
+    if (result.topic_list.categories) {
+      result.topic_list.categories.forEach((c) => {
+        Site.current().updateCategory(c);
+      });
+    }
+
+    return result.topic_list[listKey].map((t) => {
+      t.posters.forEach((p) => {
+        p.user = users[p.user_id];
+        p.extraClasses = p.extras;
+        if (p.primary_group_id) {
+          p.primary_group = groups[p.primary_group_id];
+          if (p.primary_group) {
+            p.extraClasses = `${p.extraClasses || ""} group-${
+              p.primary_group.name
+            }`;
+          }
+        }
+      });
+
+      if (t.participants) {
+        t.participants.forEach((p) => (p.user = users[p.user_id]));
+      }
+
+      return store.createRecord("topic", t);
+    });
+  }
+
+  static munge(json, store) {
+    json.inserted = json.inserted || [];
+    json.can_create_topic = json.topic_list.can_create_topic;
+    json.more_topics_url = json.topic_list.more_topics_url;
+    json.for_period = json.topic_list.for_period;
+    json.loaded = true;
+    json.per_page = json.topic_list.per_page;
+    json.topics = this.topicsFrom(store, json);
+
+    if (json.topic_list.shared_drafts) {
+      json.sharedDrafts = this.topicsFrom(store, json, {
+        listKey: "shared_drafts",
+      });
+    }
+
+    return json;
+  }
+
+  static find(filter, params) {
+    deprecated(
+      `TopicList.find is deprecated. Use \`findFiltered("topicList")\` on the \`store\` service instead.`,
+      {
+        id: "topic-list-find",
+        since: "3.1.0.beta5",
+        dropFrom: "3.2.0.beta1",
+      }
+    );
+
+    const store = getOwnerWithFallback(this).lookup("service:store");
+    return store.findFiltered("topicList", { filter, params });
+  }
+
+  // hide the category when it has no children
+  static hideUniformCategory(list, category) {
+    list.set("hideCategory", !displayCategoryInList(list.site, category));
+  }
+
+  @service session;
+
+  @notEmpty("more_topics_url") canLoadMore;
 
   forEachNew(topics, callback) {
     const topicIds = new Set();
@@ -53,7 +132,7 @@ const TopicList = RestModel.extend({
         callback(topic);
       }
     });
-  },
+  }
 
   updateSortParams(order, ascending) {
     let params = { ...(this.params || {}) };
@@ -67,7 +146,7 @@ const TopicList = RestModel.extend({
     }
 
     this.set("params", params);
-  },
+  }
 
   updateNewListSubsetParam(subset) {
     let params = { ...(this.params || {}) };
@@ -79,7 +158,7 @@ const TopicList = RestModel.extend({
     }
 
     this.set("params", params);
-  },
+  }
 
   loadMore() {
     if (this.loadingMore) {
@@ -128,7 +207,7 @@ const TopicList = RestModel.extend({
       // Return a promise indicating no more results
       return Promise.resolve();
     }
-  },
+  }
 
   // loads topics with these ids "before" the current topics
   loadBefore(topic_ids, storeInSession) {
@@ -152,87 +231,5 @@ const TopicList = RestModel.extend({
         this.session.set("topicList", this);
       }
     });
-  },
-});
-
-TopicList.reopenClass({
-  topicsFrom(store, result, opts) {
-    if (!result) {
-      return;
-    }
-
-    opts = opts || {};
-    let listKey = opts.listKey || "topics";
-
-    // Stitch together our side loaded data
-
-    const users = extractByKey(result.users, User);
-    const groups = extractByKey(result.primary_groups, EmberObject);
-
-    if (result.topic_list.categories) {
-      result.topic_list.categories.forEach((c) => {
-        Site.current().updateCategory(c);
-      });
-    }
-
-    return result.topic_list[listKey].map((t) => {
-      t.posters.forEach((p) => {
-        p.user = users[p.user_id];
-        p.extraClasses = p.extras;
-        if (p.primary_group_id) {
-          p.primary_group = groups[p.primary_group_id];
-          if (p.primary_group) {
-            p.extraClasses = `${p.extraClasses || ""} group-${
-              p.primary_group.name
-            }`;
-          }
-        }
-      });
-
-      if (t.participants) {
-        t.participants.forEach((p) => (p.user = users[p.user_id]));
-      }
-
-      return store.createRecord("topic", t);
-    });
-  },
-
-  munge(json, store) {
-    json.inserted = json.inserted || [];
-    json.can_create_topic = json.topic_list.can_create_topic;
-    json.more_topics_url = json.topic_list.more_topics_url;
-    json.for_period = json.topic_list.for_period;
-    json.loaded = true;
-    json.per_page = json.topic_list.per_page;
-    json.topics = this.topicsFrom(store, json);
-
-    if (json.topic_list.shared_drafts) {
-      json.sharedDrafts = this.topicsFrom(store, json, {
-        listKey: "shared_drafts",
-      });
-    }
-
-    return json;
-  },
-
-  find(filter, params) {
-    deprecated(
-      `TopicList.find is deprecated. Use \`findFiltered("topicList")\` on the \`store\` service instead.`,
-      {
-        id: "topic-list-find",
-        since: "3.1.0.beta5",
-        dropFrom: "3.2.0.beta1",
-      }
-    );
-
-    const store = getOwnerWithFallback(this).lookup("service:store");
-    return store.findFiltered("topicList", { filter, params });
-  },
-
-  // hide the category when it has no children
-  hideUniformCategory(list, category) {
-    list.set("hideCategory", !displayCategoryInList(list.site, category));
-  },
-});
-
-export default TopicList;
+  }
+}
diff --git a/app/assets/javascripts/discourse/app/models/topic-timer.js b/app/assets/javascripts/discourse/app/models/topic-timer.js
index 735ed43c82f..618219f36f5 100644
--- a/app/assets/javascripts/discourse/app/models/topic-timer.js
+++ b/app/assets/javascripts/discourse/app/models/topic-timer.js
@@ -1,10 +1,8 @@
 import { ajax } from "discourse/lib/ajax";
 import RestModel from "discourse/models/rest";
 
-const TopicTimer = RestModel.extend({});
-
-TopicTimer.reopenClass({
-  update(
+export default class TopicTimer extends RestModel {
+  static update(
     topicId,
     time,
     basedOnLastPost,
@@ -32,7 +30,5 @@ TopicTimer.reopenClass({
       type: "POST",
       data,
     });
-  },
-});
-
-export default TopicTimer;
+  }
+}
diff --git a/app/assets/javascripts/discourse/app/models/topic-tracking-state.js b/app/assets/javascripts/discourse/app/models/topic-tracking-state.js
index d05e53fc793..7701f9968cd 100644
--- a/app/assets/javascripts/discourse/app/models/topic-tracking-state.js
+++ b/app/assets/javascripts/discourse/app/models/topic-tracking-state.js
@@ -47,19 +47,19 @@ function hasMutedTags(topicTags, mutedTags, siteSettings) {
   );
 }
 
-const TopicTrackingState = EmberObject.extend({
-  messageCount: 0,
+export default class TopicTrackingState extends EmberObject {
+  messageCount = 0;
 
   init() {
-    this._super(...arguments);
+    super.init(...arguments);
 
     this.states = new Map();
     this.stateChangeCallbacks = {};
     this._trackedTopicLimit = 4000;
-  },
+  }
 
   willDestroy() {
-    this._super(...arguments);
+    super.willDestroy(...arguments);
 
     this.messageBus.unsubscribe("/latest", this._processChannelPayload);
 
@@ -75,7 +75,7 @@ const TopicTrackingState = EmberObject.extend({
     this.messageBus.unsubscribe("/delete", this.onDeleteMessage);
     this.messageBus.unsubscribe("/recover", this.onRecoverMessage);
     this.messageBus.unsubscribe("/destroy", this.onDestroyMessage);
-  },
+  }
 
   /**
    * Subscribe to MessageBus channels which are used for publishing changes
@@ -134,19 +134,19 @@ const TopicTrackingState = EmberObject.extend({
       this.onDestroyMessage,
       meta["/destroy"] ?? messageBusDefaultNewMessageId
     );
-  },
+  }
 
   @bind
   onDeleteMessage(msg) {
     this.modifyStateProp(msg, "deleted", true);
     this.incrementMessageCount();
-  },
+  }
 
   @bind
   onRecoverMessage(msg) {
     this.modifyStateProp(msg, "deleted", false);
     this.incrementMessageCount();
-  },
+  }
 
   @bind
   onDestroyMessage(msg) {
@@ -159,15 +159,15 @@ const TopicTrackingState = EmberObject.extend({
     ) {
       DiscourseURL.redirectTo("/");
     }
-  },
+  }
 
   mutedTopics() {
     return (this.currentUser && this.currentUser.muted_topics) || [];
-  },
+  }
 
   unmutedTopics() {
     return (this.currentUser && this.currentUser.unmuted_topics) || [];
-  },
+  }
 
   trackMutedOrUnmutedTopic(data) {
     let topics, key;
@@ -183,7 +183,7 @@ const TopicTrackingState = EmberObject.extend({
       createdAt: Date.now(),
     });
     this.currentUser && this.currentUser.set(key, topics);
-  },
+  }
 
   pruneOldMutedAndUnmutedTopics() {
     const now = Date.now();
@@ -196,15 +196,15 @@ const TopicTrackingState = EmberObject.extend({
     this.currentUser &&
       this.currentUser.set("muted_topics", mutedTopics) &&
       this.currentUser.set("unmuted_topics", unmutedTopics);
-  },
+  }
 
   isMutedTopic(topicId) {
     return !!this.mutedTopics().findBy("topicId", topicId);
-  },
+  }
 
   isUnmutedTopic(topicId) {
     return !!this.unmutedTopics().findBy("topicId", topicId);
-  },
+  }
 
   /**
    * Updates the topic's last_read_post_number to the highestSeen post
@@ -233,7 +233,7 @@ const TopicTrackingState = EmberObject.extend({
       this.modifyStateProp(topicId, "last_read_post_number", highestSeen);
       this.incrementMessageCount();
     }
-  },
+  }
 
   /**
    * Used to count incoming topics which will be displayed in a message
@@ -321,7 +321,7 @@ const TopicTrackingState = EmberObject.extend({
 
     // hasIncoming relies on this count
     this.set("incomingCount", this.newIncoming.length);
-  },
+  }
 
   /**
    * Resets the number of incoming topics to 0 and flushes the new topics
@@ -333,7 +333,7 @@ const TopicTrackingState = EmberObject.extend({
   resetTracking() {
     this.newIncoming = [];
     this.set("incomingCount", 0);
-  },
+  }
 
   /**
    * Track how many new topics came for the specified filter.
@@ -375,7 +375,7 @@ const TopicTrackingState = EmberObject.extend({
     this.set("filterTag", tag);
     this.set("filter", filter);
     this.set("incomingCount", 0);
-  },
+  }
 
   /**
    * Used to determine whether to show the message at the top of the topic list
@@ -386,7 +386,7 @@ const TopicTrackingState = EmberObject.extend({
   @discourseComputed("incomingCount")
   hasIncoming(incomingCount) {
     return incomingCount && incomingCount > 0;
-  },
+  }
 
   /**
    * Removes the topic ID provided from the tracker state.
@@ -400,7 +400,7 @@ const TopicTrackingState = EmberObject.extend({
     if (this.states.delete(this._stateKey(topicId))) {
       this._afterStateChange();
     }
-  },
+  }
 
   /**
    * Removes multiple topics from the state at once, and increments
@@ -415,7 +415,7 @@ const TopicTrackingState = EmberObject.extend({
     topicIds.forEach((topicId) => this.removeTopic(topicId));
     this.incrementMessageCount();
     this._afterStateChange();
-  },
+  }
 
   /**
    * If we have a cached topic list, we can update it from our tracking information
@@ -466,7 +466,7 @@ const TopicTrackingState = EmberObject.extend({
         });
       }
     });
-  },
+  }
 
   /**
    * Uses the provided topic list to apply changes to the in-memory topic
@@ -509,25 +509,25 @@ const TopicTrackingState = EmberObject.extend({
     }
 
     this.incrementMessageCount();
-  },
+  }
 
   incrementMessageCount() {
     this.incrementProperty("messageCount");
-  },
+  }
 
   _generateCallbackId() {
     return Math.random().toString(12).slice(2, 11);
-  },
+  }
 
   onStateChange(cb) {
     let callbackId = this._generateCallbackId();
     this.stateChangeCallbacks[callbackId] = cb;
     return callbackId;
-  },
+  }
 
   offStateChange(callbackId) {
     delete this.stateChangeCallbacks[callbackId];
-  },
+  }
 
   getSubCategoryIds(categoryId) {
     const result = [categoryId];
@@ -542,7 +542,7 @@ const TopicTrackingState = EmberObject.extend({
     }
 
     return new Set(result);
-  },
+  }
 
   countCategoryByState({
     type,
@@ -606,7 +606,7 @@ const TopicTrackingState = EmberObject.extend({
 
       return true;
     }).length;
-  },
+  }
 
   countNew({ categoryId, tagId, noSubcategories, customFilterFn } = {}) {
     return this.countCategoryByState({
@@ -616,7 +616,7 @@ const TopicTrackingState = EmberObject.extend({
       noSubcategories,
       customFilterFn,
     });
-  },
+  }
 
   countUnread({ categoryId, tagId, noSubcategories, customFilterFn } = {}) {
     return this.countCategoryByState({
@@ -626,7 +626,7 @@ const TopicTrackingState = EmberObject.extend({
       noSubcategories,
       customFilterFn,
     });
-  },
+  }
 
   countNewAndUnread({
     categoryId,
@@ -641,7 +641,7 @@ const TopicTrackingState = EmberObject.extend({
       noSubcategories,
       customFilterFn,
     });
-  },
+  }
 
   /**
    * Calls the provided callback for each of the currently tracked topics
@@ -657,7 +657,7 @@ const TopicTrackingState = EmberObject.extend({
     this._trackedTopics(opts).forEach((trackedTopic) => {
       fn(trackedTopic.topic, trackedTopic.newTopic, trackedTopic.unreadTopic);
     });
-  },
+  }
 
   /**
    * Using the array of tags provided, tallies up all topics via forEachTracked
@@ -710,7 +710,7 @@ const TopicTrackingState = EmberObject.extend({
     );
 
     return counts;
-  },
+  }
 
   countCategory(category_id, tagId) {
     let sum = 0;
@@ -728,7 +728,7 @@ const TopicTrackingState = EmberObject.extend({
       }
     }
     return sum;
-  },
+  }
 
   lookupCount({ type, category, tagId, noSubcategories, customFilterFn } = {}) {
     if (type === "latest") {
@@ -782,7 +782,7 @@ const TopicTrackingState = EmberObject.extend({
         return this.countCategory(categoryId, tagId);
       }
     }
-  },
+  }
 
   loadStates(data) {
     if (!data || data.length === 0) {
@@ -796,7 +796,7 @@ const TopicTrackingState = EmberObject.extend({
     if (modified) {
       this._afterStateChange();
     }
-  },
+  }
 
   _setState({ topic, data, skipAfterStateChange }) {
     const stateKey = this._stateKey(topic);
@@ -813,11 +813,11 @@ const TopicTrackingState = EmberObject.extend({
     } else {
       return false;
     }
-  },
+  }
 
   modifyState(topic, data) {
     this._setState({ topic, data });
-  },
+  }
 
   modifyStateProp(topic, prop, data) {
     const state = this.findState(topic);
@@ -825,11 +825,11 @@ const TopicTrackingState = EmberObject.extend({
       state[prop] = data;
       this._afterStateChange();
     }
-  },
+  }
 
   findState(topicOrId) {
     return this.states.get(this._stateKey(topicOrId));
-  },
+  }
 
   /*
    * private
@@ -860,7 +860,7 @@ const TopicTrackingState = EmberObject.extend({
         }
       }
     }
-  },
+  }
 
   // this updates the topic in the state to match the
   // topic from the list (e.g. updates category, highest read post
@@ -908,7 +908,7 @@ const TopicTrackingState = EmberObject.extend({
     }
 
     return newState;
-  },
+  }
 
   // this stops sync of tracking state when list is filtered, in the past this
   // would cause the tracking state to become inconsistent.
@@ -925,7 +925,7 @@ const TopicTrackingState = EmberObject.extend({
     }
 
     return shouldCompensate;
-  },
+  }
 
   // any state that is not in the provided list must be updated
   // based on the filter selected so we do not have any incorrect
@@ -957,7 +957,7 @@ const TopicTrackingState = EmberObject.extend({
 
       this.modifyState(topicKey, newState);
     }
-  },
+  }
 
   // processes the data sent via messageBus, called by establishChannels
   @bind
@@ -1054,7 +1054,7 @@ const TopicTrackingState = EmberObject.extend({
         this.incrementMessageCount();
       }
     }
-  },
+  }
 
   _dismissNewTopics(topicIds) {
     topicIds.forEach((topicId) => {
@@ -1062,7 +1062,7 @@ const TopicTrackingState = EmberObject.extend({
     });
 
     this.incrementMessageCount();
-  },
+  }
 
   _dismissNewPosts(topicIds) {
     topicIds.forEach((topicId) => {
@@ -1078,13 +1078,13 @@ const TopicTrackingState = EmberObject.extend({
     });
 
     this.incrementMessageCount();
-  },
+  }
 
   _addIncoming(topicId) {
     if (!this.newIncoming.includes(topicId)) {
       this.newIncoming.push(topicId);
     }
-  },
+  }
 
   _trackedTopics(opts = {}) {
     return Array.from(this.states.values())
@@ -1096,7 +1096,7 @@ const TopicTrackingState = EmberObject.extend({
         }
       })
       .compact();
-  },
+  }
 
   _stateKey(topicOrId) {
     if (typeof topicOrId === "number") {
@@ -1106,17 +1106,17 @@ const TopicTrackingState = EmberObject.extend({
     } else {
       return `t${topicOrId.topic_id}`;
     }
-  },
+  }
 
   _afterStateChange() {
     this.notifyPropertyChange("states");
     Object.values(this.stateChangeCallbacks).forEach((cb) => cb());
-  },
+  }
 
   _maxStateSizeReached() {
     return this.states.size >= this._trackedTopicLimit;
-  },
-});
+  }
+}
 
 export function startTracking(tracking) {
   PreloadStore.getAndRemove("topicTrackingStates").then((data) =>
@@ -1127,5 +1127,3 @@ export function startTracking(tracking) {
     tracking.establishChannels(meta)
   );
 }
-
-export default TopicTrackingState;
diff --git a/app/assets/javascripts/discourse/app/models/user-action-group.js b/app/assets/javascripts/discourse/app/models/user-action-group.js
index 0f48a5555f9..80db4430042 100644
--- a/app/assets/javascripts/discourse/app/models/user-action-group.js
+++ b/app/assets/javascripts/discourse/app/models/user-action-group.js
@@ -1,10 +1,10 @@
 import EmberObject from "@ember/object";
 
-export default EmberObject.extend({
+export default class UserActionGroup extends EmberObject {
   push(item) {
     if (!this.items) {
       this.items = [];
     }
     return this.items.push(item);
-  },
-});
+  }
+}
diff --git a/app/assets/javascripts/discourse/app/models/user-action-stat.js b/app/assets/javascripts/discourse/app/models/user-action-stat.js
index eeb94bf8f65..dbe2efcd3c9 100644
--- a/app/assets/javascripts/discourse/app/models/user-action-stat.js
+++ b/app/assets/javascripts/discourse/app/models/user-action-stat.js
@@ -3,16 +3,16 @@ import RestModel from "discourse/models/rest";
 import UserAction from "discourse/models/user-action";
 import discourseComputed from "discourse-common/utils/decorators";
 
-export default RestModel.extend({
+export default class UserActionStat extends RestModel {
+  @i18n("action_type", "user_action_groups.%@") description;
+
   @discourseComputed("action_type")
   isPM(actionType) {
     return (
       actionType === UserAction.TYPES.messages_sent ||
       actionType === UserAction.TYPES.messages_received
     );
-  },
-
-  description: i18n("action_type", "user_action_groups.%@"),
+  }
 
   @discourseComputed("action_type")
   isResponse(actionType) {
@@ -20,5 +20,5 @@ export default RestModel.extend({
       actionType === UserAction.TYPES.replies ||
       actionType === UserAction.TYPES.quotes
     );
-  },
-});
+  }
+}
diff --git a/app/assets/javascripts/discourse/app/models/user-action.js b/app/assets/javascripts/discourse/app/models/user-action.js
index 01e898751a5..aa194418313 100644
--- a/app/assets/javascripts/discourse/app/models/user-action.js
+++ b/app/assets/javascripts/discourse/app/models/user-action.js
@@ -26,153 +26,28 @@ Object.keys(UserActionTypes).forEach(
   (k) => (InvertedActionTypes[k] = UserActionTypes[k])
 );
 
-const UserAction = RestModel.extend({
-  @discourseComputed("category_id")
-  category() {
-    return Category.findById(this.category_id);
-  },
+export default class UserAction extends RestModel {
+  static TYPES = UserActionTypes;
 
-  @discourseComputed("action_type")
-  descriptionKey(action) {
-    if (action === null || UserAction.TO_SHOW.includes(action)) {
-      if (this.isPM) {
-        return this.sameUser ? "sent_by_you" : "sent_by_user";
-      } else {
-        return this.sameUser ? "posted_by_you" : "posted_by_user";
-      }
-    }
+  static TYPES_INVERTED = InvertedActionTypes;
 
-    if (this.topicType) {
-      return this.sameUser ? "you_posted_topic" : "user_posted_topic";
-    }
+  static TO_COLLAPSE = [
+    UserActionTypes.likes_given,
+    UserActionTypes.likes_received,
+    UserActionTypes.edits,
+    UserActionTypes.bookmarks,
+  ];
 
-    if (this.postReplyType) {
-      if (this.reply_to_post_number) {
-        return this.sameUser ? "you_replied_to_post" : "user_replied_to_post";
-      } else {
-        return this.sameUser ? "you_replied_to_topic" : "user_replied_to_topic";
-      }
-    }
+  static TO_SHOW = [
+    UserActionTypes.likes_given,
+    UserActionTypes.likes_received,
+    UserActionTypes.edits,
+    UserActionTypes.bookmarks,
+    UserActionTypes.messages_sent,
+    UserActionTypes.messages_received,
+  ];
 
-    if (this.mentionType) {
-      if (this.sameUser) {
-        return "you_mentioned_user";
-      } else {
-        return this.targetUser ? "user_mentioned_you" : "user_mentioned_user";
-      }
-    }
-  },
-
-  @discourseComputed("username")
-  sameUser(username) {
-    return username === User.currentProp("username");
-  },
-
-  @discourseComputed("target_username")
-  targetUser(targetUsername) {
-    return targetUsername === User.currentProp("username");
-  },
-
-  presentName: or("name", "username"),
-  targetDisplayName: or("target_name", "target_username"),
-  actingDisplayName: or("acting_name", "acting_username"),
-
-  @discourseComputed("target_username")
-  targetUserUrl(username) {
-    return userPath(username);
-  },
-
-  @discourseComputed("username")
-  usernameLower(username) {
-    return username.toLowerCase();
-  },
-
-  @discourseComputed("usernameLower")
-  userUrl(usernameLower) {
-    return userPath(usernameLower);
-  },
-
-  @discourseComputed()
-  postUrl() {
-    return postUrl(this.slug, this.topic_id, this.post_number);
-  },
-
-  @discourseComputed()
-  replyUrl() {
-    return postUrl(this.slug, this.topic_id, this.reply_to_post_number);
-  },
-
-  replyType: equal("action_type", UserActionTypes.replies),
-  postType: equal("action_type", UserActionTypes.posts),
-  topicType: equal("action_type", UserActionTypes.topics),
-  bookmarkType: equal("action_type", UserActionTypes.bookmarks),
-  messageSentType: equal("action_type", UserActionTypes.messages_sent),
-  messageReceivedType: equal("action_type", UserActionTypes.messages_received),
-  mentionType: equal("action_type", UserActionTypes.mentions),
-  isPM: or("messageSentType", "messageReceivedType"),
-  postReplyType: or("postType", "replyType"),
-
-  addChild(action) {
-    let groups = this.childGroups;
-    if (!groups) {
-      groups = {
-        likes: UserActionGroup.create({ icon: "heart" }),
-        stars: UserActionGroup.create({ icon: "star" }),
-        edits: UserActionGroup.create({ icon: "pencil-alt" }),
-        bookmarks: UserActionGroup.create({ icon: "bookmark" }),
-      };
-    }
-    this.set("childGroups", groups);
-
-    const bucket = (function () {
-      switch (action.action_type) {
-        case UserActionTypes.likes_given:
-        case UserActionTypes.likes_received:
-          return "likes";
-        case UserActionTypes.edits:
-          return "edits";
-        case UserActionTypes.bookmarks:
-          return "bookmarks";
-      }
-    })();
-    const current = groups[bucket];
-    if (current) {
-      current.push(action);
-    }
-  },
-
-  @discourseComputed(
-    "childGroups",
-    "childGroups.likes.items",
-    "childGroups.likes.items.[]",
-    "childGroups.stars.items",
-    "childGroups.stars.items.[]",
-    "childGroups.edits.items",
-    "childGroups.edits.items.[]",
-    "childGroups.bookmarks.items",
-    "childGroups.bookmarks.items.[]"
-  )
-  children() {
-    const g = this.childGroups;
-    let rval = [];
-    if (g) {
-      rval = [g.likes, g.stars, g.edits, g.bookmarks].filter(function (i) {
-        return i.get("items") && i.get("items").length > 0;
-      });
-    }
-    return rval;
-  },
-
-  switchToActing() {
-    this.setProperties({
-      username: this.acting_username,
-      name: this.actingDisplayName,
-    });
-  },
-});
-
-UserAction.reopenClass({
-  collapseStream(stream) {
+  static collapseStream(stream) {
     const uniq = {};
     const collapsed = [];
     let pos = 0;
@@ -204,26 +79,147 @@ UserAction.reopenClass({
       }
     });
     return collapsed;
-  },
+  }
 
-  TYPES: UserActionTypes,
-  TYPES_INVERTED: InvertedActionTypes,
+  @or("name", "username") presentName;
+  @or("target_name", "target_username") targetDisplayName;
+  @or("acting_name", "acting_username") actingDisplayName;
+  @equal("action_type", UserActionTypes.replies) replyType;
+  @equal("action_type", UserActionTypes.posts) postType;
+  @equal("action_type", UserActionTypes.topics) topicType;
+  @equal("action_type", UserActionTypes.bookmarks) bookmarkType;
+  @equal("action_type", UserActionTypes.messages_sent) messageSentType;
+  @equal("action_type", UserActionTypes.messages_received) messageReceivedType;
+  @equal("action_type", UserActionTypes.mentions) mentionType;
+  @or("messageSentType", "messageReceivedType") isPM;
+  @or("postType", "replyType") postReplyType;
 
-  TO_COLLAPSE: [
-    UserActionTypes.likes_given,
-    UserActionTypes.likes_received,
-    UserActionTypes.edits,
-    UserActionTypes.bookmarks,
-  ],
+  @discourseComputed("category_id")
+  category() {
+    return Category.findById(this.category_id);
+  }
 
-  TO_SHOW: [
-    UserActionTypes.likes_given,
-    UserActionTypes.likes_received,
-    UserActionTypes.edits,
-    UserActionTypes.bookmarks,
-    UserActionTypes.messages_sent,
-    UserActionTypes.messages_received,
-  ],
-});
+  @discourseComputed("action_type")
+  descriptionKey(action) {
+    if (action === null || UserAction.TO_SHOW.includes(action)) {
+      if (this.isPM) {
+        return this.sameUser ? "sent_by_you" : "sent_by_user";
+      } else {
+        return this.sameUser ? "posted_by_you" : "posted_by_user";
+      }
+    }
 
-export default UserAction;
+    if (this.topicType) {
+      return this.sameUser ? "you_posted_topic" : "user_posted_topic";
+    }
+
+    if (this.postReplyType) {
+      if (this.reply_to_post_number) {
+        return this.sameUser ? "you_replied_to_post" : "user_replied_to_post";
+      } else {
+        return this.sameUser ? "you_replied_to_topic" : "user_replied_to_topic";
+      }
+    }
+
+    if (this.mentionType) {
+      if (this.sameUser) {
+        return "you_mentioned_user";
+      } else {
+        return this.targetUser ? "user_mentioned_you" : "user_mentioned_user";
+      }
+    }
+  }
+
+  @discourseComputed("username")
+  sameUser(username) {
+    return username === User.currentProp("username");
+  }
+
+  @discourseComputed("target_username")
+  targetUser(targetUsername) {
+    return targetUsername === User.currentProp("username");
+  }
+
+  @discourseComputed("target_username")
+  targetUserUrl(username) {
+    return userPath(username);
+  }
+
+  @discourseComputed("username")
+  usernameLower(username) {
+    return username.toLowerCase();
+  }
+
+  @discourseComputed("usernameLower")
+  userUrl(usernameLower) {
+    return userPath(usernameLower);
+  }
+
+  @discourseComputed()
+  postUrl() {
+    return postUrl(this.slug, this.topic_id, this.post_number);
+  }
+
+  @discourseComputed()
+  replyUrl() {
+    return postUrl(this.slug, this.topic_id, this.reply_to_post_number);
+  }
+
+  addChild(action) {
+    let groups = this.childGroups;
+    if (!groups) {
+      groups = {
+        likes: UserActionGroup.create({ icon: "heart" }),
+        stars: UserActionGroup.create({ icon: "star" }),
+        edits: UserActionGroup.create({ icon: "pencil-alt" }),
+        bookmarks: UserActionGroup.create({ icon: "bookmark" }),
+      };
+    }
+    this.set("childGroups", groups);
+
+    const bucket = (function () {
+      switch (action.action_type) {
+        case UserActionTypes.likes_given:
+        case UserActionTypes.likes_received:
+          return "likes";
+        case UserActionTypes.edits:
+          return "edits";
+        case UserActionTypes.bookmarks:
+          return "bookmarks";
+      }
+    })();
+    const current = groups[bucket];
+    if (current) {
+      current.push(action);
+    }
+  }
+
+  @discourseComputed(
+    "childGroups",
+    "childGroups.likes.items",
+    "childGroups.likes.items.[]",
+    "childGroups.stars.items",
+    "childGroups.stars.items.[]",
+    "childGroups.edits.items",
+    "childGroups.edits.items.[]",
+    "childGroups.bookmarks.items",
+    "childGroups.bookmarks.items.[]"
+  )
+  children() {
+    const g = this.childGroups;
+    let rval = [];
+    if (g) {
+      rval = [g.likes, g.stars, g.edits, g.bookmarks].filter(function (i) {
+        return i.get("items") && i.get("items").length > 0;
+      });
+    }
+    return rval;
+  }
+
+  switchToActing() {
+    this.setProperties({
+      username: this.acting_username,
+      name: this.actingDisplayName,
+    });
+  }
+}
diff --git a/app/assets/javascripts/discourse/app/models/user-badge.js b/app/assets/javascripts/discourse/app/models/user-badge.js
index 5ee048e949b..122121a5a0e 100644
--- a/app/assets/javascripts/discourse/app/models/user-badge.js
+++ b/app/assets/javascripts/discourse/app/models/user-badge.js
@@ -7,34 +7,8 @@ import Topic from "discourse/models/topic";
 import User from "discourse/models/user";
 import discourseComputed from "discourse-common/utils/decorators";
 
-const UserBadge = EmberObject.extend({
-  @discourseComputed
-  postUrl() {
-    if (this.topic_title) {
-      return "/t/-/" + this.topic_id + "/" + this.post_number;
-    }
-  }, // avoid the extra bindings for now
-
-  revoke() {
-    return ajax("/user_badges/" + this.id, {
-      type: "DELETE",
-    });
-  },
-
-  favorite() {
-    this.toggleProperty("is_favorite");
-    return ajax(`/user_badges/${this.id}/toggle_favorite`, {
-      type: "PUT",
-    }).catch((e) => {
-      // something went wrong, switch the UI back:
-      this.toggleProperty("is_favorite");
-      popupAjaxError(e);
-    });
-  },
-});
-
-UserBadge.reopenClass({
-  createFromJson(json) {
+export default class UserBadge extends EmberObject {
+  static createFromJson(json) {
     // Create User objects.
     if (json.users === undefined) {
       json.users = [];
@@ -105,7 +79,7 @@ UserBadge.reopenClass({
       }
       return userBadges;
     }
-  },
+  }
 
   /**
     Find all badges for a given username.
@@ -115,7 +89,7 @@ UserBadge.reopenClass({
     @param {Object} options
     @returns {Promise} a promise that resolves to an array of `UserBadge`.
   **/
-  findByUsername(username, options) {
+  static findByUsername(username, options) {
     if (!username) {
       return Promise.resolve([]);
     }
@@ -126,7 +100,7 @@ UserBadge.reopenClass({
     return ajax(url).then(function (json) {
       return UserBadge.createFromJson(json);
     });
-  },
+  }
 
   /**
     Find all badge grants for a given badge ID.
@@ -135,7 +109,7 @@ UserBadge.reopenClass({
     @param {String} badgeId
     @returns {Promise} a promise that resolves to an array of `UserBadge`.
   **/
-  findByBadgeId(badgeId, options) {
+  static findByBadgeId(badgeId, options) {
     if (!options) {
       options = {};
     }
@@ -146,7 +120,7 @@ UserBadge.reopenClass({
     }).then(function (json) {
       return UserBadge.createFromJson(json);
     });
-  },
+  }
 
   /**
     Grant the badge having id `badgeId` to the user identified by `username`.
@@ -156,7 +130,7 @@ UserBadge.reopenClass({
     @param {String} username username of the user to be granted the badge.
     @returns {Promise} a promise that resolves to an instance of `UserBadge`.
   **/
-  grant(badgeId, username, reason) {
+  static grant(badgeId, username, reason) {
     return ajax("/user_badges", {
       type: "POST",
       data: {
@@ -167,7 +141,29 @@ UserBadge.reopenClass({
     }).then(function (json) {
       return UserBadge.createFromJson(json);
     });
-  },
-});
+  }
 
-export default UserBadge;
+  @discourseComputed
+  postUrl() {
+    if (this.topic_title) {
+      return "/t/-/" + this.topic_id + "/" + this.post_number;
+    }
+  } // avoid the extra bindings for now
+
+  revoke() {
+    return ajax("/user_badges/" + this.id, {
+      type: "DELETE",
+    });
+  }
+
+  favorite() {
+    this.toggleProperty("is_favorite");
+    return ajax(`/user_badges/${this.id}/toggle_favorite`, {
+      type: "PUT",
+    }).catch((e) => {
+      // something went wrong, switch the UI back:
+      this.toggleProperty("is_favorite");
+      popupAjaxError(e);
+    });
+  }
+}
diff --git a/app/assets/javascripts/discourse/app/models/user-draft.js b/app/assets/javascripts/discourse/app/models/user-draft.js
index 732d996454d..43056b1f0de 100644
--- a/app/assets/javascripts/discourse/app/models/user-draft.js
+++ b/app/assets/javascripts/discourse/app/models/user-draft.js
@@ -9,16 +9,16 @@ import User from "discourse/models/user";
 import discourseComputed from "discourse-common/utils/decorators";
 import I18n from "discourse-i18n";
 
-export default RestModel.extend({
+export default class UserDraft extends RestModel {
   @discourseComputed("draft_username")
   editableDraft(draftUsername) {
     return draftUsername === User.currentProp("username");
-  },
+  }
 
   @discourseComputed("username_lower")
   userUrl(usernameLower) {
     return userPath(usernameLower);
-  },
+  }
 
   @discourseComputed("topic_id")
   postUrl(topicId) {
@@ -27,7 +27,7 @@ export default RestModel.extend({
     }
 
     return postUrl(this.slug, this.topic_id, this.post_number);
-  },
+  }
 
   @discourseComputed("draft_key")
   draftType(draftKey) {
@@ -39,5 +39,5 @@ export default RestModel.extend({
       default:
         return false;
     }
-  },
-});
+  }
+}
diff --git a/app/assets/javascripts/discourse/app/models/user-drafts-stream.js b/app/assets/javascripts/discourse/app/models/user-drafts-stream.js
index f9d460e98e3..3fa13694b0c 100644
--- a/app/assets/javascripts/discourse/app/models/user-drafts-stream.js
+++ b/app/assets/javascripts/discourse/app/models/user-drafts-stream.js
@@ -10,17 +10,16 @@ import RestModel from "discourse/models/rest";
 import UserDraft from "discourse/models/user-draft";
 import discourseComputed from "discourse-common/utils/decorators";
 
-export default RestModel.extend({
-  limit: 30,
-
-  loading: false,
-  hasMore: false,
-  content: null,
+export default class UserDraftsStream extends RestModel {
+  limit = 30;
+  loading = false;
+  hasMore = false;
+  content = null;
 
   init() {
-    this._super(...arguments);
+    super.init(...arguments);
     this.reset();
-  },
+  }
 
   reset() {
     this.setProperties({
@@ -28,19 +27,19 @@ export default RestModel.extend({
       hasMore: true,
       content: [],
     });
-  },
+  }
 
   @discourseComputed("content.length", "loading")
   noContent(contentLength, loading) {
     return contentLength === 0 && !loading;
-  },
+  }
 
   remove(draft) {
     this.set(
       "content",
       this.content.filter((item) => item.draft_key !== draft.draft_key)
     );
-  },
+  }
 
   findItems(site) {
     if (site) {
@@ -92,5 +91,5 @@ export default RestModel.extend({
       .finally(() => {
         this.set("loading", false);
       });
-  },
-});
+  }
+}