Persist collapae state

frontend/src/components/Sidebar.tsx

@@ -35,6 +35,31 @@ type CollapseState = {
   repeaters: boolean;
 };
 
+const SIDEBAR_COLLAPSE_STATE_KEY = 'remoteterm-sidebar-collapse-state';
+
+const DEFAULT_COLLAPSE_STATE: CollapseState = {
+  favorites: false,
+  channels: false,
+  contacts: false,
+  repeaters: false,
+};
+
+function loadCollapsedState(): CollapseState {
+  try {
+    const raw = localStorage.getItem(SIDEBAR_COLLAPSE_STATE_KEY);
+    if (!raw) return DEFAULT_COLLAPSE_STATE;
+    const parsed = JSON.parse(raw) as Partial<CollapseState>;
+    return {
+      favorites: parsed.favorites ?? DEFAULT_COLLAPSE_STATE.favorites,
+      channels: parsed.channels ?? DEFAULT_COLLAPSE_STATE.channels,
+      contacts: parsed.contacts ?? DEFAULT_COLLAPSE_STATE.contacts,
+      repeaters: parsed.repeaters ?? DEFAULT_COLLAPSE_STATE.repeaters,
+    };
+  } catch {
+    return DEFAULT_COLLAPSE_STATE;
+  }
+}
+
 interface SidebarProps {
   contacts: Contact[];
   channels: Channel[];
@@ -75,10 +100,11 @@ export function Sidebar({
 }: SidebarProps) {
   const sortOrder = sortOrderProp;
   const [searchQuery, setSearchQuery] = useState('');
-  const [favoritesCollapsed, setFavoritesCollapsed] = useState(false);
-  const [channelsCollapsed, setChannelsCollapsed] = useState(false);
-  const [contactsCollapsed, setContactsCollapsed] = useState(false);
-  const [repeatersCollapsed, setRepeatersCollapsed] = useState(false);
+  const initialCollapsedState = useMemo(loadCollapsedState, []);
+  const [favoritesCollapsed, setFavoritesCollapsed] = useState(initialCollapsedState.favorites);
+  const [channelsCollapsed, setChannelsCollapsed] = useState(initialCollapsedState.channels);
+  const [contactsCollapsed, setContactsCollapsed] = useState(initialCollapsedState.contacts);
+  const [repeatersCollapsed, setRepeatersCollapsed] = useState(initialCollapsedState.repeaters);
   const collapseSnapshotRef = useRef<CollapseState | null>(null);
 
   const handleSortToggle = () => {
@@ -260,6 +286,23 @@ export function Sidebar({
     }
   }, [isSearching, favoritesCollapsed, channelsCollapsed, contactsCollapsed, repeatersCollapsed]);
 
+  useEffect(() => {
+    if (isSearching) return;
+
+    const state: CollapseState = {
+      favorites: favoritesCollapsed,
+      channels: channelsCollapsed,
+      contacts: contactsCollapsed,
+      repeaters: repeatersCollapsed,
+    };
+
+    try {
+      localStorage.setItem(SIDEBAR_COLLAPSE_STATE_KEY, JSON.stringify(state));
+    } catch {
+      // Ignore localStorage write failures (e.g., disabled storage)
+    }
+  }, [isSearching, favoritesCollapsed, channelsCollapsed, contactsCollapsed, repeatersCollapsed]);
+
   // Separate favorites from regular items, and build combined favorites list
   const { favoriteItems, nonFavoriteChannels, nonFavoriteContacts, nonFavoriteRepeaters } =
     useMemo(() => {

frontend/src/test/sidebar.test.tsx

@@ -1,5 +1,5 @@
 import { fireEvent, render, screen, waitFor, within } from '@testing-library/react';
-import { describe, expect, it, vi } from 'vitest';
+import { beforeEach, describe, expect, it, vi } from 'vitest';
 
 import { Sidebar } from '../components/Sidebar';
 import { CONTACT_TYPE_REPEATER, type Channel, type Contact, type Favorite } from '../types';
@@ -54,7 +54,7 @@ function renderSidebar(overrides?: {
 
   const favorites = overrides?.favorites ?? [{ type: 'channel', id: flightChannel.key }];
 
-  render(
+  const view = render(
     <Sidebar
       contacts={[alice, relay]}
       channels={[publicChannel, flightChannel, opsChannel]}
@@ -74,7 +74,7 @@ function renderSidebar(overrides?: {
     />
   );
 
-  return { flightChannel, opsChannel, aliceName };
+  return { ...view, flightChannel, opsChannel, aliceName };
 }
 
 function getSectionHeaderContainer(title: string): HTMLElement {
@@ -85,6 +85,10 @@ function getSectionHeaderContainer(title: string): HTMLElement {
 }
 
 describe('Sidebar section summaries', () => {
+  beforeEach(() => {
+    localStorage.clear();
+  });
+
   it('shows muted section unread totals in each visible section header', () => {
     renderSidebar();
 
@@ -117,4 +121,20 @@ describe('Sidebar section summaries', () => {
       expect(screen.queryByText(aliceName)).not.toBeInTheDocument();
     });
   });
+
+  it('persists collapsed section state across unmount and remount', () => {
+    const { opsChannel, aliceName, unmount } = renderSidebar();
+
+    fireEvent.click(screen.getByRole('button', { name: /Channels/i }));
+    fireEvent.click(screen.getByRole('button', { name: /Contacts/i }));
+
+    expect(screen.queryByText(opsChannel.name)).not.toBeInTheDocument();
+    expect(screen.queryByText(aliceName)).not.toBeInTheDocument();
+
+    unmount();
+    renderSidebar();
+
+    expect(screen.queryByText(opsChannel.name)).not.toBeInTheDocument();
+    expect(screen.queryByText(aliceName)).not.toBeInTheDocument();
+  });
 });