nodejs/Mongoose - Only return the Array (with all elements) of the document

Question

I have a problem with my nodejs Api I want mongoose to return me only the array of the document but not the whole document.

This are my Schemas:

//Require Mongoose
var mongoose = require('mongoose');

//Define a schema
var Schema = mongoose.Schema;

var ReplaceSchema = new Schema({
    ts: {type: Number, required: true},
    by: {type: String, required: true}
})

var ItemSchema = new Schema({
    title: {type: String, required: true},
    item: {type: String, required: true},
    ts: {type: String, required: true},
    replaced: [ReplaceSchema]
})

var ProductSchema = new Schema({
    title: {type: String, required: true, trim: true}, //name of the products
    catId: {type: String, required: true},
    ts: {type: Number, required: true},  // wehn was the product online
    buyCount: {type: Number, required: true}, // baught how many times
    description: {type: String}, //more about the product
    price: {type: Number, required: true}, // how much?
    items: [ItemSchema]
});

var CategorySchema = new Schema({
    name: {type: String, required: true},
    ts: {type: Number, required: true},
    products: [ProductSchema]
});


var Category = mongoose.model('Category', CategorySchema, 'Category');
module.exports = Category;

This is the Function in the Model which should fetch the Array

module.exports.getProductsOfCategory = function (catId, callback) {
    Category.find({'products.catId': catId}, callback)
};

last but not least this is what happens when the route is hit:

router.post('/productsofcategory', function (req, res) {
    var catId = req.body.id;
    console.log(catId)

    Category.getProductsOfCategory(catId, function (err, products) {
        if (err) {
            res.send(err)
        } else {

            res.send(products)
        }
    })
})

MY Problem better explained:

Im getting this:

[
    {
        "_id": "5998dc248c28a03974272da4",
        "ts": 1503190052760,
        "name": "Testcat1",
        "__v": 4,
        "products": [
            {
                "title": "testprod2",
                "catId": "5998dc248c28a03974272da4",
                "ts": 1500642848744,
                "buyCount": 0,
                "description": "this is just a test",
                "price": 9.99,
                "_id": "5998dc6a0c864d397a5bfd3d",
                "items": []
            },
            {
                "title": "testprod2",
                "catId": "5998dc248c28a03974272da4",
                "ts": 1500642848744,
                "buyCount": 0,
                "description": "this is just a test",
                "price": 9.99,
                "_id": "5998dc710c864d397a5bfd3e",
                "items": []
            },
            {
                "title": "testProdukt",
                "description": "<p>tsetnietsiseiD</p>",
                "price": 14.99,
                "catId": "5998dc248c28a03974272da4",
                "ts": 1503237239393,
                "buyCount": 0,
                "_id": "59999477a5b6e63e60733220",
                "items": []
            },
            {
                "title": "aaaaa",
                "description": "<p>asasasas</p>",
                "price": 12,
                "catId": "5998dc248c28a03974272da4",
                "ts": 1503237690437,
                "buyCount": 0,
                "_id": "5999963a68a3d63ee65a8546",
                "items": []
            }
        ]
    }
]

But i just want to have this:

"products": [
            {
                "title": "testprod2",
                "catId": "5998dc248c28a03974272da4",
                "ts": 1500642848744,
                "buyCount": 0,
                "description": "this is just a test",
                "price": 9.99,
                "_id": "5998dc6a0c864d397a5bfd3d",
                "items": []
            },
            {
                "title": "testprod2",
                "catId": "5998dc248c28a03974272da4",
                "ts": 1500642848744,
                "buyCount": 0,
                "description": "this is just a test",
                "price": 9.99,
                "_id": "5998dc710c864d397a5bfd3e",
                "items": []
            },
            {
                "title": "testProdukt",
                "description": "<p>tsetnietsiseiD</p>",
                "price": 14.99,
                "catId": "5998dc248c28a03974272da4",
                "ts": 1503237239393,
                "buyCount": 0,
                "_id": "59999477a5b6e63e60733220",
                "items": []
            },
            {
                "title": "aaaaa",
                "description": "<p>asasasas</p>",
                "price": 12,
                "catId": "5998dc248c28a03974272da4",
                "ts": 1503237690437,
                "buyCount": 0,
                "_id": "5999963a68a3d63ee65a8546",
                "items": []
            }
        ]

Answer 1

Just select the specific field you want:

Category.find({'products.catId': catId}, 'products', callback)

or in your response, change

res.send(products) to res.send(products[0].products)

Answer 2

write query to select specific fields

module.exports.getProductsOfCategory = function (catId, callback) {
    Category.find({'products.catId': catId},['products'], callback)
};