B: Correctly process invalid manuals topic name

rsconcept/frontend/src/app/Router.tsx

@@ -28,6 +28,10 @@ export const Router = createBrowserRouter([
         path: '',
         element: <HomePage />
       },
+      {
+        path: `${routes.not_found}`,
+        element: <NotFoundPage />
+      },
       {
         path: routes.login,
         element: <LoginPage />

rsconcept/frontend/src/app/urls.ts

@@ -8,6 +8,7 @@ import { buildConstants } from '@/utils/buildConstants';
  * Routes.
  */
 export const routes = {
+  not_found: 'not-found',
   login: 'login',
   signup: 'signup',
   profile: 'profile',
@@ -39,6 +40,7 @@ interface OssProps {
  * Internal navigation URLs.
  */
 export const urls = {
+  page404: '/not-found',
   admin: `${buildConstants.backend}/admin`,
   rest_api: `${buildConstants.backend}/`,
   home: '/',

rsconcept/frontend/src/pages/ManualsPage/ManualsPage.tsx

@@ -7,6 +7,7 @@ import { useConceptOptions } from '@/context/ConceptOptionsContext';
 import { useConceptNavigation } from '@/context/NavigationContext';
 import useQueryStrings from '@/hooks/useQueryStrings';
 import { HelpTopic } from '@/models/miscellaneous';
+import { PARAMETER } from '@/utils/constants';
 
 import TopicsList from './TopicsList';
 import ViewTopic from './ViewTopic';
@@ -18,6 +19,14 @@ function ManualsPage() {
 
   const { mainHeight } = useConceptOptions();
 
+  if (!Object.values(HelpTopic).includes(activeTopic)) {
+    setTimeout(() => {
+      router.push(urls.page404);
+    }, PARAMETER.refreshTimeout);
+    console.log(1);
+    return null;
+  }
+
   const onSelectTopic = useCallback(
     (newTopic: HelpTopic) => {
       router.push(urls.help_topic(newTopic));