feat(react): basic implementation of note title

apps/client/src/widgets/basic_widget.ts

@@ -5,6 +5,7 @@ import { t } from "../services/i18n.js";
 import toastService from "../services/toast.js";
 import { renderReactWidget } from "./react/react_utils.jsx";
 import { EventNames, EventData } from "../components/app_context.js";
+import { Handler } from "leaflet";
 
 export class TypedBasicWidget<T extends TypedComponent<any>> extends TypedComponent<T> {
     protected attrs: Record<string, string>;
@@ -277,10 +278,12 @@ export function wrapReactWidgets<T extends TypedComponent<any>>(components: (T |
     return wrappedResult;
 }
 
+type EventHandler = ((data: any) => void);
+
 export class ReactWrappedWidget extends BasicWidget {
 
     private el: VNode;
-    listeners: Record<string, (data: any) => void> = {};
+    private listeners: Record<string, EventHandler[]> = {};
 
     constructor(el: VNode) {
         super();
@@ -292,8 +295,38 @@ export class ReactWrappedWidget extends BasicWidget {
     }
 
     handleEvent<T extends EventNames>(name: T, data: EventData<T>): Promise<unknown[] | unknown> | null | undefined {
-        const listener = this.listeners[name];
-        listener?.(data);
+        if (!this.listeners[name]) {
+            return;
+        }
+
+        for (const listener of this.listeners[name]) {
+            listener(data);
+        }
+    }
+
+    registerHandler<T extends EventNames>(name: T, handler: EventHandler) {
+        if (!this.listeners[name]) {
+            this.listeners[name] = [];
+        }
+
+        if (this.listeners[name].includes(handler)) {
+            return;
+        }
+
+        this.listeners[name].push(handler);
+    }
+
+    removeHandler<T extends EventNames>(name: T, handler: EventHandler) {
+        if (!this.listeners[name]?.includes(handler)) {
+            return;
+        }
+
+        this.listeners[name] = this.listeners[name]
+            .filter(listener => listener !== handler);
+
+        if (!this.listeners[name].length) {
+            delete this.listeners[name];
+        }
     }
 
 }