node.js - Save array of ObjectId in Schema -

i have model called shop whos schema looks this:

'use strict';  var mongoose = require('mongoose'),     schema = mongoose.schema;  var shopschema = new schema({   name: { type: string, required: true },   address: { type: string, required: true },   description: string,   stock: { type: number, default: 100 },   latitude: { type: number, required: true },   longitude: { type: number, required: true },   image: string,   link: string,   tags: [{ type: schema.objectid, ref: 'tag' }],   createdat: { type: date, default: date.now },   updatedat: { type: date, default: date.now } });  module.exports = mongoose.model('shop', shopschema); 

i want use array tags reference model via objectid obviously. set works fine when add ids property via db.shops.update({...}, {$set: {tags: ...}}) , ids set properly. when try via express.js controller assigned model, nothing gets updated , there no error message. here update function in controller:

// updates existing shop in db. exports.update = function(req, res) {   if(req.body._id) { delete req.body._id; }   shop.findbyid(req.params.id, function (err, shop) {     if (err) { return handleerror(res, err); }     if(!shop) { return res.send(404); }     var updated = _.merge(shop, req.body);     shop.updatedat = new date();     updated.save(function (err) {       if (err) { return handleerror(res, err); }       return res.json(200, shop);     });   }); }; 

this works perfect other properties of shop model not tags. tried set type of tags string, didn't help.

i guess missing saving arrays in mongoose?

it looks issue _.merge() cannot handle merging arrays properly, tags array in case. workaround adding explicit assignment of tags array after merge, if ok overwrite existing tags.

var updated = _.merge(shop, req.body); if (req.body.tags) {   updated.tags = req.body.tags; }  

hope helps.. if workaround not sufficient may visit lodash forums.