import Users from 'meteor/nova:users'; Users.isSubscribedTo = (user, document) => { // return user && document && document.subscribers && document.subscribers.indexOf(user._id) !== -1; if (!user || !document) { // should return an error return false; } const { __typename, _id: itemId } = document; const documentType = __typename + 's'; if (user.subscribedItems && user.subscribedItems[documentType]) { return !!user.subscribedItems[documentType].find(subscribedItems => subscribedItems.itemId === itemId); } else { return false; } };