some-hook.jsx

  const TCUserQuery = useCallback(() => {
    return Object.keys(defaultTCs).map((tc) =>
      rtdb.ref(`users/${tc}`).once('value'),
    );
  }, [defaultTCs, rtdb]);

  useEffect(() => {
    async function getTCContacts() {
      const transactionCoordinatorsResponse = await Promise.all([TCUserQuery()]);

      const transactionCoordinators =
        Array.isArray(transactionCoordinatorsResponse) &&
        transactionCoordinatorsResponse.map((tc) => {
          if (!tc?.val) return null;
          return processResponse(tc.val());
        });

      setContactState({
        contacts: {
          transactionCoordinators,
        },
      });
    }

    getTCContacts();
  }, [TCUserQuery, TCTransactionContactsQuery]);