diff --git a/lib/hooks/search-threads.js b/lib/hooks/search-threads.js
--- a/lib/hooks/search-threads.js
+++ b/lib/hooks/search-threads.js
@@ -6,9 +6,9 @@
   type ChatThreadItem,
   useFilteredChatListData,
 } from '../selectors/chat-selectors';
+import { useThreadSearchIndex } from '../selectors/nav-selectors';
 import { sidebarInfoSelector } from '../selectors/thread-selectors';
-import SearchIndex from '../shared/search-index';
-import { threadIsChannel, threadSearchText } from '../shared/thread-utils';
+import { threadIsChannel } from '../shared/thread-utils';
 import type { SetState } from '../types/hook-types';
 import type {
   SidebarInfo,
@@ -39,8 +39,6 @@
     results: new Set<string>(),
   });
 
-  const userInfos = useSelector(state => state.userStore.userInfos);
-
   const listData = React.useMemo(() => {
     if (!searchState.text) {
       return childThreadInfos;
@@ -50,20 +48,9 @@
     );
   }, [childThreadInfos, searchState]);
 
-  const viewerID = useSelector(
-    state => state.currentUserInfo && state.currentUserInfo.id,
+  const searchIndex = useThreadSearchIndex(
+    childThreadInfos.map(childThreadInfo => childThreadInfo.threadInfo),
   );
-  const searchIndex = React.useMemo(() => {
-    const index = new SearchIndex();
-    for (const thread of childThreadInfos) {
-      const threadInfoFromItem = thread.threadInfo;
-      index.addEntry(
-        threadInfoFromItem.id,
-        threadSearchText(threadInfoFromItem, userInfos, viewerID),
-      );
-    }
-    return index;
-  }, [childThreadInfos, userInfos, viewerID]);
 
   const onChangeSearchInputText = React.useCallback(
     (text: string) => {
diff --git a/lib/selectors/nav-selectors.js b/lib/selectors/nav-selectors.js
--- a/lib/selectors/nav-selectors.js
+++ b/lib/selectors/nav-selectors.js
@@ -1,5 +1,6 @@
 // @flow
 
+import * as React from 'react';
 import { createSelector } from 'reselect';
 
 import SearchIndex from '../shared/search-index';
@@ -9,9 +10,10 @@
 import type { CalendarFilter } from '../types/filter-types';
 import type { BaseNavInfo } from '../types/nav-types';
 import type { BaseAppState } from '../types/redux-types';
-import type { RawThreadInfo } from '../types/thread-types';
+import type { RawThreadInfo, ThreadInfo } from '../types/thread-types';
 import type { UserInfos } from '../types/user-types';
 import { getConfig } from '../utils/config';
+import { useSelector } from '../utils/redux-utils';
 
 function timeUntilCalendarRangeExpiration(
   lastUserInteractionCalendar: number,
@@ -65,6 +67,25 @@
   },
 );
 
+function useThreadSearchIndex(
+  threadInfos: $ReadOnlyArray<RawThreadInfo | ThreadInfo>,
+): SearchIndex {
+  const userInfos = useSelector(state => state.userStore.userInfos);
+  const viewerID = useSelector(
+    state => state.currentUserInfo && state.currentUserInfo.id,
+  );
+  return React.useMemo(() => {
+    const searchIndex = new SearchIndex();
+    for (const threadInfo of threadInfos) {
+      searchIndex.addEntry(
+        threadInfo.id,
+        threadSearchText(threadInfo, userInfos, viewerID),
+      );
+    }
+    return searchIndex;
+  }, [threadInfos, userInfos, viewerID]);
+}
+
 const threadSearchIndex: (
   state: BaseAppState<*>,
 ) => SearchIndex = createSelector(
@@ -92,4 +113,5 @@
   timeUntilCalendarRangeExpiration,
   currentCalendarQuery,
   threadSearchIndex,
+  useThreadSearchIndex,
 };