feat: JS Notification extender (#3974)

* feat: JS `Notification` extender

* fix

framework/core/js/src/common/extenders/Notification.ts

@@ -0,0 +1,25 @@
+import IExtender, { IExtensionModule } from './IExtender';
+import type Component from '../Component';
+import ForumApplication from '../../forum/ForumApplication';
+import type Application from '../Application';
+import type { NewComponent } from '../Application';
+
+export default class Notification implements IExtender {
+  private notificationComponents: Record<string, new () => Component> = {};
+
+  /**
+   * Register a new notification component type.
+   *
+   * @param name The name of the notification type.
+   * @param component The component class to render the notification.
+   */
+  add(name: string, component: NewComponent<any>): Notification {
+    this.notificationComponents[name] = component;
+
+    return this;
+  }
+
+  extend(app: Application, extension: IExtensionModule): void {
+    Object.assign((app as unknown as ForumApplication).notificationComponents, this.notificationComponents);
+  }
+}

framework/core/js/src/common/extenders/index.ts

@@ -3,6 +3,7 @@ import PostTypes from './PostTypes';
 import Routes from './Routes';
 import Store from './Store';
 import Search from './Search';
+import Notification from './Notification';
 
 const extenders = {
   Model,
@@ -10,6 +11,7 @@ const extenders = {
   Routes,
   Store,
   Search,
+  Notification,
 };
 
 export default extenders;