Adding strong checks on messages exchanged using generic-type-guard

front/src/Api/Events/ChatEvent.ts

@@ -0,0 +1,8 @@
+import * as tg from "generic-type-guard";
+
+export const isChatEvent =
+    new tg.IsInterface().withProperties({
+        message: tg.isString,
+        author: tg.isString,
+    }).get();
+export type ChatEvent = tg.GuardedType<typeof isChatEvent>;

front/src/Api/Events/IframeEvent.ts

@@ -0,0 +1,7 @@
+interface IframeEvent {
+    type: string;
+    data: unknown;
+}
+
+// eslint-disable-next-line @typescript-eslint/no-explicit-any
+export const isIframeEventWrapper = (event: any): event is IframeEvent => typeof event.type === 'string' && typeof event.data === 'object';

front/src/Api/IframeListener.ts

@@ -1,9 +1,8 @@
 import {Subject} from "rxjs";
+import {ChatEvent, isChatEvent} from "./Events/ChatEvent";
+import {isIframeEventWrapper} from "./Events/IframeEvent";
+
 
-interface ChatEvent {
-    message: string,
-    author: string
-}
 
 /**
  * Listens to messages from iframes and turn those messages into easy to use observables.
@@ -21,12 +20,14 @@ class IframeListener {
             // event.source is window.opener
             // event.data is the data sent by the iframe
 
-            // FIXME: this is WAAAAAAAY too sloppy as "any" let's us put anything in the message.
-
-            if (event.data.type === 'chat') {
-                this._chatStream.next(event.data.data);
+            const payload = event.data;
+            if (isIframeEventWrapper(payload)) {
+                if (payload.type === 'chat' && isChatEvent(payload.data)) {
+                    this._chatStream.next(payload.data);
+                }
             }
 
+
         }, false);
     }
 }