query based on deep relations

export const findOrCreateChat = async (fromID: number, toID: number) => {
  const existingchat = await db.query.chats.findFirst({
    with: { members: true },
     where(fields, { and, eq }) {
      // the line below needs fix.
      return and(eq(chatMembers.userID, fromID), eq(chatMembers.userID, toID));
     },

  });
  if (existingchat) {
    return existingchat;
  }

  const newChat = await db
    .insert(chats)
    .values({
      name: `new chat`,
    })
    .returning();

  await db.insert(chatMembers).values([
    { chatID: newChat[0].id, userID: fromID },
    { chatID: newChat[0].id, userID: toID },
  ]);

  return newChat[0];
};