diff --git a/js/src/common/Application.js b/js/src/common/Application.js
index 94e631cf2..9cbf0bab2 100644
--- a/js/src/common/Application.js
+++ b/js/src/common/Application.js
@@ -12,6 +12,7 @@ import mapRoutes from './utils/mapRoutes';
 import RequestError from './utils/RequestError';
 import ScrollListener from './utils/ScrollListener';
 import liveHumanTimes from './utils/liveHumanTimes';
+import patchMithril from './utils/patchMithril';
 import { extend } from './extend';
 
 import Forum from './models/Forum';
@@ -166,6 +167,8 @@ export default class Application {
   }
 
   boot() {
+    patchMithril(window);
+
     this.initializers.toArray().forEach((initializer) => initializer(this));
 
     this.store.pushPayload({ data: this.data.resources });
diff --git a/js/src/common/FlarumRegistry.ts b/js/src/common/FlarumRegistry.ts
new file mode 100644
index 000000000..a342b8668
--- /dev/null
+++ b/js/src/common/FlarumRegistry.ts
@@ -0,0 +1,60 @@
+interface ExportRegistry {
+  moduleExports: object;
+
+  onLoads: object;
+
+  /**
+   * Add an instance to the registry.
+   * This serves as the equivalent of `flarum.core.compat[id] = object`
+   */
+  add(namespace: string, id: string, object: any): void;
+
+  /**
+   * Add a function to run when object of id "id" is added (or overriden).
+   * If such an object is already registered, the handler will be applied immediately.
+   */
+  onLoad(namespace: string, id: string, handler: Function): void;
+
+  /**
+   * Retrieve an object of type `id` from the registry.
+   */
+  get(namespace: string, id: string): any;
+}
+
+export default class FlarumRegistry implements ExportRegistry {
+  moduleExports = new Map<string, any>();
+  onLoads = new Map<string, Function[]>();
+
+  protected genKey(namespace: string, id: string): string {
+    return `${namespace};${id}`;
+  }
+
+  add(namespace: string, id: string, object: any) {
+    const key = this.genKey(namespace, id);
+
+    const onLoads = this.onLoads.get(key);
+    if (onLoads) {
+      onLoads.reduce((acc, handler) => handler(acc), object);
+    }
+
+    this.moduleExports.set(key, object);
+  }
+
+  onLoad(namespace: string, id: string, handler: Function) {
+    const key = this.genKey(namespace, id);
+
+    const loadedObject = this.moduleExports.get(key);
+    if (loadedObject) {
+      this.moduleExports[id] = handler(loadedObject);
+    } else {
+      const currOnLoads = this.onLoads.get(key);
+      this.onLoads.set(key, [...(currOnLoads || []), handler]);
+    }
+  }
+
+  get(namespace: string, id: string): any {
+    const key = this.genKey(namespace, id);
+
+    return this.moduleExports.get(key);
+  }
+}
diff --git a/js/src/common/index.js b/js/src/common/index.js
index c2d576780..dfb1a1b02 100644
--- a/js/src/common/index.js
+++ b/js/src/common/index.js
@@ -1,5 +1,5 @@
 // Expose jQuery, mithril and dayjs to the window browser object
-import 'expose-loader?exposes[]=$&exposes[]=jQuery!jquery';
+import 'expose-loader?exposes=$,jQuery!jquery';
 import 'expose-loader?exposes=m!mithril';
 import 'expose-loader?exposes=dayjs!dayjs';
 
@@ -16,9 +16,9 @@ import localizedFormat from 'dayjs/plugin/localizedFormat';
 dayjs.extend(relativeTime);
 dayjs.extend(localizedFormat);
 
-import patchMithril from './utils/patchMithril';
+import FlarumRegistry from './FlarumRegistry';
 
-patchMithril(window);
+window.flreg = new FlarumRegistry();
 
 import * as Extend from './extend/index';