Игорь Попов

var ObjectId = mongoose.Types.ObjectId; // объявляем ObjectId

var sendPhotoRemovePush = function (user) {
   return mongoose.model('Notice')
       .findById(ObjectId("5b1055bab772d4a8c93dc0cf"), function (err, notice) {
           var message = {
               to: user.gcmId,
               notification: {
                   title: user.locale == 'en' ? notice.titleEn : notice.titleRu,
                   body: user.locale == 'en' ? notice.bodyEn : notice.bodyRu,
                   sound: notice.sound
               }
           };
           sendPush(message);
       });
};