mongoose modify multi level subdocument then save not work normally

Question

I have a Torrent item, it has subdocument array named '_replies' to saved user comments, and every comment also include subdocument array '_replies' to saved user reply, this is my all schema define:

var CommentSchema = new Schema({
  user: {
    type: Schema.Types.ObjectId,
    ref: 'User'
  },
  comment: {
    type: String,
    default: '',
    trim: true
  },
  _replies: [this],
  createdat: {
    type: Date,
    default: Date.now
  },
  editedby: {
    type: String,
    default: '',
    trim: true
  },
  editedat: {
    type: Date,
    default: ''
  }
});

var TorrentSchema = new Schema({
  user: {
    type: Schema.Types.ObjectId,
    ref: 'User'
  },
  torrent_filename: {
    type: String,
    default: '',
    trim: true,
    required: 'filename cannot be blank'
  },
  torrent_title: {
    type: String,
    default: '',
    trim: true,
    required: 'title cannot be blank'
  },
  _replies: [CommentSchema]
});

mongoose.model('Torrent', TorrentSchema);
mongoose.model('Comment', CommentSchema);

the first level comment of torrent update/delete fine, the code of server controller likes below:

exports.update = function (req, res) {
  var torrent = req.torrent;

  torrent._replies.forEach(function (r) {
    if (r._id.equals(req.params.commentId)) {
      r.comment = req.body.comment;
      r.editedat = Date.now();
      r.editedby = req.user.displayName;

      torrent.save(function (err) {
        if (err) {
          return res.status(422).send({
            message: errorHandler.getErrorMessage(err)
          });
        } else {
          res.json(torrent); //return data is Correct, and save to mongo is Correct
        }
      });
    }
  });
};

but when i used Alike function to update/delete _replies._replies, it can return Correct json of torrent to response, Unfortunate, the save to mongo not fine, the code:

exports.SubUpdate = function (req, res) {
  var torrent = req.torrent;

  torrent._replies.forEach(function (r) {
    if (r._id.equals(req.params.commentId)) {
      r._replies.forEach(function (s) {
        if (s._id.equals(req.params.subCommentId)) {
          s.comment = req.body.comment;
          s.editedat = Date.now();
          s.editedby = req.user.displayName;

          torrent.save(function (err) {
            if (err) {
              return res.status(422).send({
                message: errorHandler.getErrorMessage(err)
              });
            } else {
              res.json(torrent);//return data is Correct, but save to mongo is incorrect
            }
          });
        }
      });
    }
  });
};

also, i can delete first level comment, but can not delete second level comment reply, all the json data of torrent is correct, only not save to mongo.

what can i do more?

Answer 1

I already solve it, i add this code before .save().

torrent.markModified('_replies');

it work fine!