diff --git a/lib/selectors/chat-selectors.js b/lib/selectors/chat-selectors.js
--- a/lib/selectors/chat-selectors.js
+++ b/lib/selectors/chat-selectors.js
@@ -23,6 +23,10 @@
   sortMessageInfoList,
 } from '../shared/message-utils.js';
 import { messageSpecs } from '../shared/messages/message-specs.js';
+import {
+  getSidebarItems,
+  type SidebarItem,
+} from '../shared/sidebar-item-utils.js';
 import { threadInChatList, threadIsPending } from '../shared/thread-utils.js';
 import { messageTypes } from '../types/message-types-enum.js';
 import {
@@ -39,32 +43,15 @@
 } from '../types/minimally-encoded-thread-permissions-types.js';
 import type { BaseAppState } from '../types/redux-types.js';
 import { threadTypeIsSidebar } from '../types/thread-types-enum.js';
-import {
-  maxReadSidebars,
-  maxUnreadSidebars,
-  type SidebarInfo,
-} from '../types/thread-types.js';
 import type {
   AccountUserInfo,
   RelativeUserInfo,
   UserInfo,
 } from '../types/user-types.js';
-import { threeDays } from '../utils/date-utils.js';
 import type { EntityText } from '../utils/entity-text.js';
 import memoize2 from '../utils/memoize.js';
 import { useSelector } from '../utils/redux-utils.js';
 
-export type SidebarItem =
-  | {
-      ...SidebarInfo,
-      +type: 'sidebar',
-    }
-  | {
-      +type: 'seeMore',
-      +unread: boolean,
-    }
-  | { +type: 'spacer' };
-
 export type ChatThreadItem = {
   +type: 'chatThreadItem',
   +threadInfo: ThreadInfo,
@@ -121,47 +108,7 @@
           ? Math.max(lastUpdatedTime, allSidebarItems[0].lastUpdatedTime)
           : lastUpdatedTime;
 
-      const numUnreadSidebars = allSidebarItems.filter(
-        sidebar => sidebar.threadInfo.currentUser.unread,
-      ).length;
-      let numReadSidebarsToShow = maxReadSidebars - numUnreadSidebars;
-      const threeDaysAgo = Date.now() - threeDays;
-
-      const sidebarItems: SidebarItem[] = [];
-      for (const sidebar of allSidebarItems) {
-        if (sidebarItems.length >= maxUnreadSidebars) {
-          break;
-        } else if (sidebar.threadInfo.currentUser.unread) {
-          sidebarItems.push(sidebar);
-        } else if (
-          sidebar.lastUpdatedTime > threeDaysAgo &&
-          numReadSidebarsToShow > 0
-        ) {
-          sidebarItems.push(sidebar);
-          numReadSidebarsToShow--;
-        }
-      }
-
-      const numReadButRecentSidebars = allSidebarItems.filter(
-        sidebar =>
-          !sidebar.threadInfo.currentUser.unread &&
-          sidebar.lastUpdatedTime > threeDaysAgo,
-      ).length;
-      if (
-        sidebarItems.length < numUnreadSidebars + numReadButRecentSidebars ||
-        (sidebarItems.length < allSidebarItems.length &&
-          sidebarItems.length > 0)
-      ) {
-        sidebarItems.push({
-          type: 'seeMore',
-          unread: numUnreadSidebars > maxUnreadSidebars,
-        });
-      }
-      if (sidebarItems.length !== 0) {
-        sidebarItems.push({
-          type: 'spacer',
-        });
-      }
+      const sidebarItems = getSidebarItems(allSidebarItems);
 
       return {
         type: 'chatThreadItem',
diff --git a/lib/shared/sidebar-item-utils.js b/lib/shared/sidebar-item-utils.js
new file mode 100644
--- /dev/null
+++ b/lib/shared/sidebar-item-utils.js
@@ -0,0 +1,68 @@
+// @flow
+
+import type { ThreadInfo } from '../types/minimally-encoded-thread-permissions-types.js';
+import { maxReadSidebars, maxUnreadSidebars } from '../types/thread-types.js';
+import { threeDays } from '../utils/date-utils.js';
+
+type SidebarThreadItem = {
+  +type: 'sidebar',
+  +threadInfo: ThreadInfo,
+  +mostRecentNonLocalMessage: ?string,
+  +lastUpdatedTime: number,
+};
+export type SidebarItem =
+  | SidebarThreadItem
+  | {
+      +type: 'seeMore',
+      +unread: boolean,
+    }
+  | { +type: 'spacer' };
+
+function getSidebarItems(
+  allSidebarItems: $ReadOnlyArray<SidebarThreadItem>,
+): SidebarItem[] {
+  const numUnreadSidebars = allSidebarItems.filter(
+    sidebar => sidebar.threadInfo.currentUser.unread,
+  ).length;
+  let numReadSidebarsToShow = maxReadSidebars - numUnreadSidebars;
+  const threeDaysAgo = Date.now() - threeDays;
+
+  const sidebarItems: SidebarItem[] = [];
+  for (const sidebar of allSidebarItems) {
+    if (sidebarItems.length >= maxUnreadSidebars) {
+      break;
+    } else if (sidebar.threadInfo.currentUser.unread) {
+      sidebarItems.push(sidebar);
+    } else if (
+      sidebar.lastUpdatedTime > threeDaysAgo &&
+      numReadSidebarsToShow > 0
+    ) {
+      sidebarItems.push(sidebar);
+      numReadSidebarsToShow--;
+    }
+  }
+
+  const numReadButRecentSidebars = allSidebarItems.filter(
+    sidebar =>
+      !sidebar.threadInfo.currentUser.unread &&
+      sidebar.lastUpdatedTime > threeDaysAgo,
+  ).length;
+  if (
+    sidebarItems.length < numUnreadSidebars + numReadButRecentSidebars ||
+    (sidebarItems.length < allSidebarItems.length && sidebarItems.length > 0)
+  ) {
+    sidebarItems.push({
+      type: 'seeMore',
+      unread: numUnreadSidebars > maxUnreadSidebars,
+    });
+  }
+  if (sidebarItems.length !== 0) {
+    sidebarItems.push({
+      type: 'spacer',
+    });
+  }
+
+  return sidebarItems;
+}
+
+export { getSidebarItems };
diff --git a/lib/shared/thread-utils.js b/lib/shared/thread-utils.js
--- a/lib/shared/thread-utils.js
+++ b/lib/shared/thread-utils.js
@@ -12,6 +12,7 @@
 import { generatePendingThreadColor } from './color-utils.js';
 import { extractUserMentionsFromText } from './mention-utils.js';
 import { relationshipBlockedInEitherDirection } from './relationship-utils.js';
+import type { SidebarItem } from './sidebar-item-utils.js';
 import ashoat from '../facts/ashoat.js';
 import genesis from '../facts/genesis.js';
 import { useLoggedInUserInfo } from '../hooks/account-hooks.js';
@@ -30,10 +31,7 @@
   getAllThreadPermissions,
   makePermissionsBlob,
 } from '../permissions/thread-permissions.js';
-import type {
-  ChatThreadItem,
-  SidebarItem,
-} from '../selectors/chat-selectors.js';
+import type { ChatThreadItem } from '../selectors/chat-selectors.js';
 import {
   threadInfoSelector,
   pendingToRealizedThreadIDsSelector,