Function useFilteredChildThreads

lib/hooks/child-threads.js:27–132

(
  threadID: string,
  filter?: ThreadFilter,
)

};

function useFilteredChildThreads(
  threadID: string,
  filter?: ThreadFilter,
): $ReadOnlyArray<ChatThreadItem> {
  const defaultPredicate = React.useCallback(() => true, []);
  const { predicate = defaultPredicate, searchText = '' } = filter ?? {};
  const childThreads = useSelector(state => childThreadInfos(state)[threadID]);
  const subchannelIDs = React.useMemo(() => {
    if (!childThreads) {
      return new Set<string>();
    }
    return new Set<string>(
      childThreads.filter(predicate).map(threadInfo => threadInfo.id),
    );
  }, [childThreads, predicate]);

  const filterSubchannels = React.useCallback(
    (thread: ?(RawThreadInfo | ThreadInfo)) => {
      const candidateThreadID = thread?.id;
      if (!candidateThreadID) {
        return false;
      }
      return subchannelIDs.has(candidateThreadID);
    },
    [subchannelIDs],
  );
  const allSubchannelsList = useFilteredChatListData(filterSubchannels);

  const searchIndex = useGlobalThreadSearchIndex();

  const searchResultIDs = React.useMemo(
    () => searchIndex.getSearchResults(searchText),
    [searchIndex, searchText],
  );

  const searchTextExists = !!searchText.length;

  const subchannelsThreadInfos = React.useMemo(
    () => allSubchannelsList.map(item => item.threadInfo),
    [allSubchannelsList],
  );
  const subchannelsInChatList = useThreadsInChatList(subchannelsThreadInfos);
  const subchannelIDsInChatList = React.useMemo(
    () => new Set(subchannelsInChatList.map(thread => thread.id)),
    [subchannelsInChatList],
  );

  const subchannelIDsNotInChatList = React.useMemo(
    () =>
      new Set(
        allSubchannelsList
          .filter(item => !subchannelIDsInChatList.has(item.threadInfo.id))
          .map(item => item.threadInfo.id),
      ),
    [allSubchannelsList, subchannelIDsInChatList],
  );

  React.useEffect(() => {