diff --git a/lib/selectors/chat-selectors.js b/lib/selectors/chat-selectors.js
index 18b6dfc7a..95ede5c4c 100644
--- a/lib/selectors/chat-selectors.js
+++ b/lib/selectors/chat-selectors.js
@@ -1,766 +1,761 @@
 // @flow
 
 import invariant from 'invariant';
 import _orderBy from 'lodash/fp/orderBy.js';
 import * as React from 'react';
 import { createSelector } from 'reselect';
 import { createObjectSelector } from 'reselect-map';
 
 import {
   threadInfoFromSourceMessageIDSelector,
   threadInfoSelector,
 } from './thread-selectors.js';
 import { useSidebarInfos } from '../hooks/sidebar-hooks.js';
 import { useGetLastUpdatedTimes } from '../hooks/thread-time.js';
 import {
   createMessageInfo,
   getMostRecentNonLocalMessageID,
   messageKey,
   robotextForMessageInfo,
   sortMessageInfoList,
 } from '../shared/message-utils.js';
 import { messageSpecs } from '../shared/messages/message-specs.js';
 import {
   getSidebarItems,
   getAllInitialSidebarItems,
   getAllFinalSidebarItems,
   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 {
   type ComposableMessageInfo,
   isComposableMessageType,
   type LocalMessageInfo,
   type MessageInfo,
   type MessageStore,
   type RobotextMessageInfo,
 } from '../types/message-types.js';
 import type {
   ThreadInfo,
   RawThreadInfo,
 } 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 type {
   AccountUserInfo,
   RelativeUserInfo,
   UserInfo,
 } from '../types/user-types.js';
 import type { EntityText } from '../utils/entity-text.js';
 import memoize2 from '../utils/memoize.js';
 import { useSelector } from '../utils/redux-utils.js';
 
 export type ChatThreadItem = {
   +type: 'chatThreadItem',
   +threadInfo: ThreadInfo,
   +mostRecentNonLocalMessage: ?string,
   +sidebars: $ReadOnlyArray<SidebarItem>,
   +pendingPersonalThreadUserInfo?: UserInfo,
   +lastUpdatedTime: number,
   +lastUpdatedTimeIncludingSidebars: number,
 };
 
 const messageInfoSelector: (state: BaseAppState<>) => {
   +[id: string]: ?MessageInfo,
 } = createObjectSelector(
   (state: BaseAppState<>) => state.messageStore.messages,
   (state: BaseAppState<>) => state.currentUserInfo && state.currentUserInfo.id,
   (state: BaseAppState<>) => state.userStore.userInfos,
   threadInfoSelector,
   createMessageInfo,
 );
 
 function isEmptyMediaMessage(messageInfo: MessageInfo): boolean {
   return (
     (messageInfo.type === messageTypes.MULTIMEDIA ||
       messageInfo.type === messageTypes.IMAGES) &&
     messageInfo.media.length === 0
   );
 }
 
-type CreatedChatThreadItem = {
+type ChatThreadItemLoader = {
   +threadInfo: ThreadInfo,
   +lastUpdatedAtLeastTimeIncludingSidebars: number,
   +lastUpdatedAtMostTimeIncludingSidebars: number,
   +initialChatThreadItem: ChatThreadItem,
   +getFinalChatThreadItem: () => Promise<ChatThreadItem>,
 };
-function useCreateChatThreadItem(): ThreadInfo => CreatedChatThreadItem {
+function useGetChatThreadItemLoader(): ThreadInfo => ChatThreadItemLoader {
   const messageInfos = useSelector(messageInfoSelector);
   const sidebarInfos = useSidebarInfos();
   const messageStore = useSelector(state => state.messageStore);
   const getLastUpdatedTimes = useGetLastUpdatedTimes();
   return React.useCallback(
     threadInfo => {
       const mostRecentNonLocalMessage = getMostRecentNonLocalMessageID(
         threadInfo.id,
         messageStore,
       );
 
       const { lastUpdatedTime, lastUpdatedAtLeastTime, lastUpdatedAtMostTime } =
         getLastUpdatedTimes(threadInfo, messageStore, messageInfos);
 
       const sidebars = sidebarInfos[threadInfo.id] ?? [];
       const chatThreadItemBase = {
         type: 'chatThreadItem',
         threadInfo,
         mostRecentNonLocalMessage,
       };
 
       const getFinalChatThreadItem = async () => {
         const lastUpdatedTimePromise = lastUpdatedTime();
 
         const lastUpdatedTimeIncludingSidebarsPromise = (async () => {
           const lastUpdatedTimePromises = [
             lastUpdatedTimePromise,
             ...sidebars.map(sidebar => sidebar.lastUpdatedTime()),
           ];
           const lastUpdatedTimes = await Promise.all(lastUpdatedTimePromises);
           const max = lastUpdatedTimes.reduce((a, b) => Math.max(a, b), -1);
           return max;
         })();
 
         const [
           lastUpdatedTimeResult,
           lastUpdatedTimeIncludingSidebars,
           allSidebarItems,
         ] = await Promise.all([
           lastUpdatedTimePromise,
           lastUpdatedTimeIncludingSidebarsPromise,
           getAllFinalSidebarItems(sidebars),
         ]);
 
         return {
           ...chatThreadItemBase,
           sidebars: getSidebarItems(allSidebarItems),
           lastUpdatedTime: lastUpdatedTimeResult,
           lastUpdatedTimeIncludingSidebars: lastUpdatedTimeIncludingSidebars,
         };
       };
 
       const lastUpdatedAtLeastTimeIncludingSidebars =
         sidebars.length > 0
           ? Math.max(lastUpdatedAtLeastTime, sidebars[0].lastUpdatedAtLeastTime)
           : lastUpdatedAtLeastTime;
 
       const lastUpdatedAtMostTimeIncludingSidebars =
         sidebars.length > 0
           ? Math.max(lastUpdatedAtMostTime, sidebars[0].lastUpdatedAtMostTime)
           : lastUpdatedAtMostTime;
 
       const allInitialSidebarItems = getAllInitialSidebarItems(sidebars);
       const initialChatThreadItem = {
         ...chatThreadItemBase,
         sidebars: getSidebarItems(allInitialSidebarItems),
         lastUpdatedTime: lastUpdatedAtLeastTime,
         lastUpdatedTimeIncludingSidebars:
           lastUpdatedAtLeastTimeIncludingSidebars,
       };
 
       return {
         threadInfo,
         lastUpdatedAtLeastTimeIncludingSidebars,
         lastUpdatedAtMostTimeIncludingSidebars,
         initialChatThreadItem,
         getFinalChatThreadItem,
       };
     },
     [messageInfos, messageStore, sidebarInfos, getLastUpdatedTimes],
   );
 }
 
 function useFlattenedChatListData(): $ReadOnlyArray<ChatThreadItem> {
   return useFilteredChatListData(threadInChatList);
 }
 
 function useFilteredChatListData(
   filterFunction: (threadInfo: ?(ThreadInfo | RawThreadInfo)) => boolean,
 ): $ReadOnlyArray<ChatThreadItem> {
   const threadInfos = useSelector(threadInfoSelector);
   const filteredThreadInfos = React.useMemo(
     () => Object.values(threadInfos).filter(filterFunction),
     [threadInfos, filterFunction],
   );
   return useChatThreadItems(filteredThreadInfos);
 }
 
 const sortFunc = _orderBy('lastUpdatedTimeIncludingSidebars')('desc');
 function useChatThreadItems(
   threadInfos: $ReadOnlyArray<ThreadInfo>,
 ): $ReadOnlyArray<ChatThreadItem> {
-  const getChatThreadItem = useCreateChatThreadItem();
-  const createdChatThreadItems = React.useMemo(
-    () => threadInfos.map(getChatThreadItem),
-    [threadInfos, getChatThreadItem],
+  const getChatThreadItemLoader = useGetChatThreadItemLoader();
+  const chatThreadItemLoaders = React.useMemo(
+    () => threadInfos.map(getChatThreadItemLoader),
+    [threadInfos, getChatThreadItemLoader],
   );
 
   const initialChatThreadItems = React.useMemo(
-    () =>
-      createdChatThreadItems.map(
-        createdChatThreadItem => createdChatThreadItem.initialChatThreadItem,
-      ),
-    [createdChatThreadItems],
+    () => chatThreadItemLoaders.map(loader => loader.initialChatThreadItem),
+    [chatThreadItemLoaders],
   );
 
   const [chatThreadItems, setChatThreadItems] = React.useState<
     $ReadOnlyArray<ChatThreadItem>,
   >(initialChatThreadItems);
 
-  const prevCreatedChatThreadItemsRef = React.useRef(createdChatThreadItems);
+  const prevChatThreadItemLoadersRef = React.useRef(chatThreadItemLoaders);
   React.useEffect(() => {
-    if (createdChatThreadItems === prevCreatedChatThreadItemsRef.current) {
+    if (chatThreadItemLoaders === prevChatThreadItemLoadersRef.current) {
       return;
     }
-    prevCreatedChatThreadItemsRef.current = createdChatThreadItems;
+    prevChatThreadItemLoadersRef.current = chatThreadItemLoaders;
 
     setChatThreadItems(initialChatThreadItems);
 
     void (async () => {
       const finalChatThreadItems = await Promise.all(
-        createdChatThreadItems.map(createdChatThreadItem =>
-          createdChatThreadItem.getFinalChatThreadItem(),
-        ),
+        chatThreadItemLoaders.map(loader => loader.getFinalChatThreadItem()),
       );
-      if (createdChatThreadItems !== prevCreatedChatThreadItemsRef.current) {
+      if (chatThreadItemLoaders !== prevChatThreadItemLoadersRef.current) {
         // If these aren't equal, it indicates that the effect has fired again.
         // We should discard this result as it is now outdated.
         return;
       }
       // The callback below is basically
       // setChatThreadItems(finalChatThreadItems), but it has extra logic to
       // preserve objects if they are unchanged.
       setChatThreadItems(prevChatThreadItems => {
         if (prevChatThreadItems.length !== finalChatThreadItems.length) {
           console.log(
             'unexpected: prevChatThreadItems.length !== ' +
               'finalChatThreadItems.length',
           );
           return finalChatThreadItems;
         }
         let somethingChanged = false;
         const result: Array<ChatThreadItem> = [];
         for (let i = 0; i < prevChatThreadItems.length; i++) {
           const prevChatThreadItem = prevChatThreadItems[i];
           const newChatThreadItem = finalChatThreadItems[i];
           if (
             prevChatThreadItem.threadInfo.id !== newChatThreadItem.threadInfo.id
           ) {
             console.log(
               'unexpected: prevChatThreadItem.threadInfo.id !== ' +
                 'newChatThreadItem.threadInfo.id',
             );
             return finalChatThreadItems;
           }
           if (
             prevChatThreadItem.lastUpdatedTime !==
               newChatThreadItem.lastUpdatedTime ||
             prevChatThreadItem.lastUpdatedTimeIncludingSidebars !==
               newChatThreadItem.lastUpdatedTimeIncludingSidebars ||
             prevChatThreadItem.sidebars.length !==
               newChatThreadItem.sidebars.length
           ) {
             somethingChanged = true;
             result[i] = newChatThreadItem;
             continue;
           }
           const sidebarsMatching = prevChatThreadItem.sidebars.every(
             (prevSidebar, j) => {
               const newSidebar = newChatThreadItem.sidebars[j];
               if (
                 newSidebar.type !== 'sidebar' ||
                 prevSidebar.type !== 'sidebar'
               ) {
                 return newSidebar.type === prevSidebar.type;
               }
               return newSidebar.threadInfo.id === prevSidebar.threadInfo.id;
             },
           );
           if (!sidebarsMatching) {
             somethingChanged = true;
             result[i] = newChatThreadItem;
             continue;
           }
           result[i] = prevChatThreadItem;
         }
         if (somethingChanged) {
           return result;
         } else {
           return prevChatThreadItems;
         }
       });
     })();
-  }, [createdChatThreadItems, initialChatThreadItems]);
+  }, [chatThreadItemLoaders, initialChatThreadItems]);
 
   return React.useMemo(() => sortFunc(chatThreadItems), [chatThreadItems]);
 }
 
 export type RobotextChatMessageInfoItem = {
   +itemType: 'message',
   +messageInfoType: 'robotext',
   +messageInfos: $ReadOnlyArray<RobotextMessageInfo>,
   +startsConversation: boolean,
   +startsCluster: boolean,
   endsCluster: boolean,
   +robotext: EntityText,
   +threadCreatedFromMessage: ?ThreadInfo,
   +reactions: ReactionInfo,
 };
 export type ComposableChatMessageInfoItem = {
   +itemType: 'message',
   +messageInfoType: 'composable',
   +messageInfo: ComposableMessageInfo,
   +localMessageInfo: ?LocalMessageInfo,
   +startsConversation: boolean,
   +startsCluster: boolean,
   endsCluster: boolean,
   +threadCreatedFromMessage: ?ThreadInfo,
   +reactions: ReactionInfo,
   +hasBeenEdited: boolean,
   +isPinned: boolean,
 };
 export type ChatMessageInfoItem =
   | RobotextChatMessageInfoItem
   | ComposableChatMessageInfoItem;
 export type ChatMessageItem = { itemType: 'loader' } | ChatMessageInfoItem;
 
 export type ReactionInfo = { +[reaction: string]: MessageReactionInfo };
 type MessageReactionInfo = {
   +viewerReacted: boolean,
   +users: $ReadOnlyArray<RelativeUserInfo>,
 };
 type TargetMessageReactions = Map<string, Map<string, RelativeUserInfo>>;
 
 const msInFiveMinutes = 5 * 60 * 1000;
 function createChatMessageItems(
   threadID: string,
   messageStore: MessageStore,
   messageInfos: { +[id: string]: ?MessageInfo },
   threadInfos: { +[id: string]: ThreadInfo },
   threadInfoFromSourceMessageID: {
     +[id: string]: ThreadInfo,
   },
   additionalMessages: $ReadOnlyArray<MessageInfo>,
   viewerID: string,
 ): ChatMessageItem[] {
   const thread = messageStore.threads[threadID];
 
   const threadMessageInfos = (thread?.messageIDs ?? [])
     .map((messageID: string) => messageInfos[messageID])
     .filter(Boolean);
   const messages =
     additionalMessages.length > 0
       ? sortMessageInfoList([...threadMessageInfos, ...additionalMessages])
       : threadMessageInfos;
 
   const targetMessageReactionsMap = new Map<string, TargetMessageReactions>();
 
   // We need to iterate backwards to put the order of messages in chronological
   // order, starting with the oldest. This avoids the scenario where the most
   // recent message with the remove_reaction action may try to remove a user
   // that hasn't been added to the messageReactionUsersInfoMap, causing it
   // to be skipped.
   for (let i = messages.length - 1; i >= 0; i--) {
     const messageInfo = messages[i];
     if (messageInfo.type !== messageTypes.REACTION) {
       continue;
     }
 
     if (!targetMessageReactionsMap.has(messageInfo.targetMessageID)) {
       const reactsMap: TargetMessageReactions = new Map();
       targetMessageReactionsMap.set(messageInfo.targetMessageID, reactsMap);
     }
 
     const messageReactsMap = targetMessageReactionsMap.get(
       messageInfo.targetMessageID,
     );
     invariant(messageReactsMap, 'messageReactsInfo should be set');
 
     if (!messageReactsMap.has(messageInfo.reaction)) {
       const usersInfoMap = new Map<string, RelativeUserInfo>();
       messageReactsMap.set(messageInfo.reaction, usersInfoMap);
     }
 
     const messageReactionUsersInfoMap = messageReactsMap.get(
       messageInfo.reaction,
     );
     invariant(
       messageReactionUsersInfoMap,
       'messageReactionUsersInfoMap should be set',
     );
 
     if (messageInfo.action === 'add_reaction') {
       messageReactionUsersInfoMap.set(
         messageInfo.creator.id,
         messageInfo.creator,
       );
     } else {
       messageReactionUsersInfoMap.delete(messageInfo.creator.id);
     }
   }
 
   const targetMessageEditMap = new Map<string, string>();
   for (let i = messages.length - 1; i >= 0; i--) {
     const messageInfo = messages[i];
     if (messageInfo.type !== messageTypes.EDIT_MESSAGE) {
       continue;
     }
     targetMessageEditMap.set(messageInfo.targetMessageID, messageInfo.text);
   }
 
   const targetMessagePinStatusMap = new Map<string, boolean>();
   // Once again, we iterate backwards to put the order of messages in
   // chronological order (i.e. oldest to newest) to handle pinned messages.
   // This is important because we want to make sure that the most recent pin
   // action is the one that is used to determine whether a message
   // is pinned or not.
   for (let i = messages.length - 1; i >= 0; i--) {
     const messageInfo = messages[i];
     if (messageInfo.type !== messageTypes.TOGGLE_PIN) {
       continue;
     }
 
     targetMessagePinStatusMap.set(
       messageInfo.targetMessageID,
       messageInfo.action === 'pin',
     );
   }
 
   const chatMessageItems: ChatMessageItem[] = [];
   let lastMessageInfo = null;
   for (let i = messages.length - 1; i >= 0; i--) {
     const messageInfo = messages[i];
 
     if (
       messageInfo.type === messageTypes.REACTION ||
       messageInfo.type === messageTypes.EDIT_MESSAGE
     ) {
       continue;
     }
 
     let originalMessageInfo =
       messageInfo.type === messageTypes.SIDEBAR_SOURCE
         ? messageInfo.sourceMessage
         : messageInfo;
 
     if (isEmptyMediaMessage(originalMessageInfo)) {
       continue;
     }
 
     let hasBeenEdited = false;
     if (
       originalMessageInfo.type === messageTypes.TEXT &&
       originalMessageInfo.id
     ) {
       const newText = targetMessageEditMap.get(originalMessageInfo.id);
       if (newText !== undefined) {
         hasBeenEdited = true;
         originalMessageInfo = {
           ...originalMessageInfo,
           text: newText,
         };
       }
     }
 
     let startsConversation = true;
     let startsCluster = true;
     if (
       lastMessageInfo &&
       lastMessageInfo.time + msInFiveMinutes > originalMessageInfo.time
     ) {
       startsConversation = false;
       if (
         isComposableMessageType(lastMessageInfo.type) &&
         isComposableMessageType(originalMessageInfo.type) &&
         lastMessageInfo.creator.id === originalMessageInfo.creator.id
       ) {
         startsCluster = false;
       }
     }
     if (startsCluster && chatMessageItems.length > 0) {
       const lastMessageItem = chatMessageItems[chatMessageItems.length - 1];
       invariant(lastMessageItem.itemType === 'message', 'should be message');
       lastMessageItem.endsCluster = true;
     }
     const threadCreatedFromMessage =
       !threadTypeIsSidebar(threadInfos[threadID]?.type) && messageInfo.id
         ? threadInfoFromSourceMessageID[messageInfo.id]
         : undefined;
 
     const isPinned = !!(
       originalMessageInfo.id &&
       targetMessagePinStatusMap.get(originalMessageInfo.id)
     );
 
     const renderedReactions: ReactionInfo = (() => {
       const result: { [string]: MessageReactionInfo } = {};
 
       let messageReactsMap;
       if (originalMessageInfo.id) {
         messageReactsMap = targetMessageReactionsMap.get(
           originalMessageInfo.id,
         );
       }
 
       if (!messageReactsMap) {
         return result;
       }
 
       for (const reaction of messageReactsMap.keys()) {
         const reactionUsersInfoMap = messageReactsMap.get(reaction);
         invariant(reactionUsersInfoMap, 'reactionUsersInfoMap should be set');
 
         if (reactionUsersInfoMap.size === 0) {
           continue;
         }
 
         const reactionUserInfos = [...reactionUsersInfoMap.values()];
 
         const messageReactionInfo = {
           users: reactionUserInfos,
           viewerReacted: reactionUsersInfoMap.has(viewerID),
         };
 
         result[reaction] = messageReactionInfo;
       }
 
       return result;
     })();
 
     const threadInfo = threadInfos[threadID];
     const parentThreadInfo = threadInfo?.parentThreadID
       ? threadInfos[threadInfo.parentThreadID]
       : null;
 
     const lastChatMessageItem =
       chatMessageItems.length > 0
         ? chatMessageItems[chatMessageItems.length - 1]
         : undefined;
     const messageSpec = messageSpecs[originalMessageInfo.type];
     if (
       !threadCreatedFromMessage &&
       Object.keys(renderedReactions).length === 0 &&
       !hasBeenEdited &&
       !isPinned &&
       lastChatMessageItem &&
       lastChatMessageItem.itemType === 'message' &&
       lastChatMessageItem.messageInfoType === 'robotext' &&
       !lastChatMessageItem.threadCreatedFromMessage &&
       Object.keys(lastChatMessageItem.reactions).length === 0 &&
       !isComposableMessageType(originalMessageInfo.type) &&
       messageSpec?.mergeIntoPrecedingRobotextMessageItem
     ) {
       const { mergeIntoPrecedingRobotextMessageItem } = messageSpec;
       const mergeResult = mergeIntoPrecedingRobotextMessageItem(
         originalMessageInfo,
         lastChatMessageItem,
         { threadInfo, parentThreadInfo },
       );
       if (mergeResult.shouldMerge) {
         chatMessageItems[chatMessageItems.length - 1] = mergeResult.item;
         continue;
       }
     }
 
     if (isComposableMessageType(originalMessageInfo.type)) {
       // We use these invariants instead of just checking the messageInfo.type
       // directly in the conditional above so that isComposableMessageType can
       // be the source of truth
       invariant(
         originalMessageInfo.type === messageTypes.TEXT ||
           originalMessageInfo.type === messageTypes.IMAGES ||
           originalMessageInfo.type === messageTypes.MULTIMEDIA,
         "Flow doesn't understand isComposableMessageType above",
       );
       const localMessageInfo =
         messageStore.local[messageKey(originalMessageInfo)];
       chatMessageItems.push({
         itemType: 'message',
         messageInfoType: 'composable',
         messageInfo: originalMessageInfo,
         localMessageInfo,
         startsConversation,
         startsCluster,
         endsCluster: false,
         threadCreatedFromMessage,
         reactions: renderedReactions,
         hasBeenEdited,
         isPinned,
       });
     } else {
       invariant(
         originalMessageInfo.type !== messageTypes.TEXT &&
           originalMessageInfo.type !== messageTypes.IMAGES &&
           originalMessageInfo.type !== messageTypes.MULTIMEDIA,
         "Flow doesn't understand isComposableMessageType above",
       );
       const robotext = robotextForMessageInfo(
         originalMessageInfo,
         threadInfo,
         parentThreadInfo,
       );
       chatMessageItems.push({
         itemType: 'message',
         messageInfoType: 'robotext',
         messageInfos: [originalMessageInfo],
         startsConversation,
         startsCluster,
         endsCluster: false,
         threadCreatedFromMessage,
         robotext,
         reactions: renderedReactions,
       });
     }
     lastMessageInfo = originalMessageInfo;
   }
   if (chatMessageItems.length > 0) {
     const lastMessageItem = chatMessageItems[chatMessageItems.length - 1];
     invariant(lastMessageItem.itemType === 'message', 'should be message');
     lastMessageItem.endsCluster = true;
   }
   chatMessageItems.reverse();
   const hideSpinner = thread ? thread.startReached : threadIsPending(threadID);
   if (hideSpinner) {
     return chatMessageItems;
   }
   return [...chatMessageItems, ({ itemType: 'loader' }: ChatMessageItem)];
 }
 
 const baseMessageListData = (
   threadID: ?string,
   additionalMessages: $ReadOnlyArray<MessageInfo>,
 ): ((state: BaseAppState<>) => ?(ChatMessageItem[])) =>
   createSelector(
     (state: BaseAppState<>) => state.messageStore,
     messageInfoSelector,
     threadInfoSelector,
     threadInfoFromSourceMessageIDSelector,
     (state: BaseAppState<>) =>
       state.currentUserInfo && state.currentUserInfo.id,
     (
       messageStore: MessageStore,
       messageInfos: { +[id: string]: ?MessageInfo },
       threadInfos: {
         +[id: string]: ThreadInfo,
       },
       threadInfoFromSourceMessageID: {
         +[id: string]: ThreadInfo,
       },
       viewerID: ?string,
     ): ?(ChatMessageItem[]) => {
       if (!threadID || !viewerID) {
         return null;
       }
       return createChatMessageItems(
         threadID,
         messageStore,
         messageInfos,
         threadInfos,
         threadInfoFromSourceMessageID,
         additionalMessages,
         viewerID,
       );
     },
   );
 export type MessageListData = ?(ChatMessageItem[]);
 const messageListData: (
   threadID: ?string,
   additionalMessages: $ReadOnlyArray<MessageInfo>,
 ) => (state: BaseAppState<>) => MessageListData = memoize2(baseMessageListData);
 
 export type UseMessageListDataArgs = {
   +searching: boolean,
   +userInfoInputArray: $ReadOnlyArray<AccountUserInfo>,
   +threadInfo: ?ThreadInfo,
 };
 
 function useMessageListData({
   searching,
   userInfoInputArray,
   threadInfo,
 }: UseMessageListDataArgs): MessageListData {
   const messageInfos = useSelector(messageInfoSelector);
 
   const containingThread = useSelector(state => {
     if (
       !threadInfo ||
       !threadTypeIsSidebar(threadInfo.type) ||
       !threadInfo.containingThreadID
     ) {
       return null;
     }
     return state.messageStore.threads[threadInfo.containingThreadID];
   });
 
   const pendingSidebarEditMessageInfo = React.useMemo(() => {
     const sourceMessageID = threadInfo?.sourceMessageID;
     const threadMessageInfos = (containingThread?.messageIDs ?? [])
       .map((messageID: string) => messageInfos[messageID])
       .filter(Boolean)
       .filter(
         message =>
           message.type === messageTypes.EDIT_MESSAGE &&
           message.targetMessageID === sourceMessageID,
       );
     if (threadMessageInfos.length === 0) {
       return null;
     }
     return threadMessageInfos[0];
   }, [threadInfo, containingThread, messageInfos]);
 
   const pendingSidebarSourceMessageInfo = useSelector(state => {
     const sourceMessageID = threadInfo?.sourceMessageID;
     if (
       !threadInfo ||
       !threadTypeIsSidebar(threadInfo.type) ||
       !sourceMessageID
     ) {
       return null;
     }
     const thread = state.messageStore.threads[threadInfo.id];
     const shouldSourceBeAdded =
       !thread ||
       (thread.startReached &&
         thread.messageIDs.every(
           id => messageInfos[id]?.type !== messageTypes.SIDEBAR_SOURCE,
         ));
     return shouldSourceBeAdded ? messageInfos[sourceMessageID] : null;
   });
 
   invariant(
     !pendingSidebarSourceMessageInfo ||
       pendingSidebarSourceMessageInfo.type !== messageTypes.SIDEBAR_SOURCE,
     'sidebars can not be created from sidebar_source message',
   );
 
   const additionalMessages = React.useMemo(() => {
     if (!pendingSidebarSourceMessageInfo) {
       return ([]: MessageInfo[]);
     }
     const result: MessageInfo[] = [pendingSidebarSourceMessageInfo];
     if (pendingSidebarEditMessageInfo) {
       result.push(pendingSidebarEditMessageInfo);
     }
     return result;
   }, [pendingSidebarSourceMessageInfo, pendingSidebarEditMessageInfo]);
   const boundMessageListData = useSelector(
     messageListData(threadInfo?.id, additionalMessages),
   );
 
   return React.useMemo(() => {
     if (searching && userInfoInputArray.length === 0) {
       return [];
     }
     return boundMessageListData;
   }, [searching, userInfoInputArray.length, boundMessageListData]);
 }
 
 export {
   messageInfoSelector,
   createChatMessageItems,
   messageListData,
   useFlattenedChatListData,
   useFilteredChatListData,
   useChatThreadItems,
   useMessageListData,
 };