populate embed array mongoose 5.0. Nested ref - node.js

Question

This is the first model. It's located in the folder called models/user.js
'use strict'
var mongoose = require('mongoose');
var Schema = mongoose.Schema;
var UserSchema = Schema({
publications: [{
description: String,
categories: [{
type: Schema.Types.ObjectId,
ref: 'Category.subcategories'
}]
}]
The model category. It's located in the folder called models/category.js
'use strict'
var mongoose = require('mongoose');
var Schema = mongoose.Schema;
var CategorySchema = Schema({
name: String,
subcategories: [{
name: String
}]
});
Look that The UserSchema has categories. This one has this reference:
ref: 'Category.subcategories'
I have a folder called controller. The next json is from controller/category.js
'use strict'
var Categories = require('./models/category');
function getCategories(req, res){
Categories.find({},(err, categories) =>{
if(err){
res.status(500).send({ message: 'Error en la peticion' });
return;
}
if(!categories){
res.status(404).send({ message: 'No hay categories' });
return
}
res.status(200).send({ categories });
});
}
module.exports = {
getCategories
}
The json of Category looks like this.
{
"categories": [
{
"subcategories": [
{
"_id": "5ae4a8b0a7510e3bd80917db",
"name": "subcategory1"
},
{
"_id": "5ae4a8b0a7510e3bd80917da",
"name": "subcategory2"
},
{
"_id": "5ae4a8b0a7510e3bd80917d9",
"name": "subcategory3"
}
],
"_id": "5ae4a8b0a7510e3bd80917d7",
"name": "Category1",
"__v": 0
},
{
"subcategories": [
{
"_id": "5ae4a8b0a7510e3bd80917e0",
"name": "subcategory1"
},
{
"_id": "5ae4a8b0a7510e3bd80917df",
"name": "subcategory2"
}
],
"_id": "5ae4a8b0a7510e3bd80917dc",
"name": "Category2",
"__v": 0
}
]
}
Each subcategory2 belongs to one Category.
This one is in controller/user.js
The user whithout populate will looks like this
User.find({}, (err, publications) => {
if (err) {
res.status(500).send({
message: "Error en la peticion " + err
});
return;
}
if (!publications) {
res.status(404).send({
message: "Publicacion no encontrada"
});
return;
}
res.status(200).send(publications);
result
"publications": [
{
"description": "abc",
"categories": [
"5ae4a8b0a7510e3bd80917db",
"5ae4a8b0a7510e3bd80917da"
]
},
{
"description": "abcddvas asa",
"categories": [
"5ae4a8b0a7510e3bd80917e0"
]
},
]
I need to populate categories when I do this.
User.find().populate('publications.categories').then(function (err, posa) {
if (err) {
res.status(500).send(err);
return;
}
res.status(500).send(posa);
return;
});
So the final json should look like this:
"publications": [
{
"description": "abc",
"categories": [
{
"_id": "5ae4a8b0a7510e3bd80917db",
"name": "subcategory1"
},
{
"_id": "5ae4a8b0a7510e3bd80917da",
"name": "subcategory2"
}
]
},
{
"description": "abcddvas asa",
"categories": [
{
"_id": "5ae4a8b0a7510e3bd80917e0",
"name": "subcategory1"
}
]
},
]
But The result does not show me the final json.
I see that there is a option called Dynamic References.
http://mongoosejs.com/docs/populate.html
The example show this
var userSchema = new Schema({
name: String,
connections: [{
kind: String,
item: { type: ObjectId, refPath: 'connections.kind' }
}]
});
Instead of use ref, uses refPath. But for me didn't work that.
I tried to use this
https://github.com/buunguyen/mongoose-deep-populate
but that didn't work for me.
I tried to do a lot of tries. None works for me. I have been searching days and trying a lot of things but I have not been able to resolve this.