query to display subdocument not working - node.js

Question

I'm fairly new to mongoose and I am trying to write a query that just returns a subdocument within my main document.
My document structure is like this:
PROFILE
- CONTACTS [ARRAY]
I've written the following endpoint to return one contact, where I pass the profile id and the id of the subdocument:
"/:owerId/getcontact/:contactId"
My Express function code looks like this:
router.route('/:ownerId/getcontact/:contactId')
.get(function(req, res){
Profile.findOne({'owner_id':req.params.ownerId}).then(function(err, profile){
if(err)
res.send(err);
profile.findOne({'_id':req.params.contactId}).then(function(err, contact){
if(err)
res.send(err);
res.json(contact);
})
})
})
But this code returns the whole profile.
When I try to get by ID it does the same thing. Here is my code and just below that is the entire profile that is returned:
router.route('/:ownerId/getcontact/:contactId')
.get(function(req, res){
Profile.findById(req.params.ownerId).then(function(err, profile){
if(err)
res.send(err);
var data = profile.contacts.id(req.params.contactId);
res.json(data);
})
})
{
"_id": "5886e3692ca4542c453431ee",
"initial": "u",
"last_name": "randal",
"first_name": "chris",
"owner_id": "5886e32c2ca4542c453431ed",
"__v": 1,
"contacts": [
{
"last_name": "Eltoro",
"first_name": "Peter",
"_id": "5886e3f5a219472cac886a9f",
"businesses": [],
"addresses": [],
"phones": [
{
"phone_type": "mobile",
"phone_number": "555-555-999",
"_id": "5886e3f5a219472cac886aa2"
},
{
"phone_type": "home",
"phone_number": "999-876-000",
"_id": "5886e3f5a219472cac886aa1"
}
],
"emails": [
{
"email_address": "tim#time.com",
"_id": "5886e3f5a219472cac886aa0"
}
]
},
{
"college": "University of WA",
"highschool": "Kalaheo",
"birthday": "1990-12-22T08:00:00.000Z",
"last_name": "Smith",
"first_name": "Suzanne",
"_id": "5886fb7fac288c2e31eabe0a",
"businesses": [],
"addresses": [
{
"zip": "98777",
"state": "WA",
"city": "Seattle",
"address_2": "Apt 234",
"address": "124 194th St. SW",
"_id": "5886fb7fac288c2e31eabe0e"
}
],
"phones": [
{
"phone_type": "mobile",
"phone_number": "206-899-9898",
"_id": "5886fb7fac288c2e31eabe0d"
},
{
"phone_type": "home",
"phone_number": "206-789-0987",
"_id": "5886fb7fac288c2e31eabe0c"
}
],
"emails": [
{
"email_type": "personal",
"email_address": "suzanne#smith.com",
"_id": "5886fb7fac288c2e31eabe0b"
}
]
},
{
"last_name": "Alabaster",
"first_name": "Cindy",
"_id": "5888b0bd3c025e54476828d9",
"businesses": [],
"addresses": [],
"phones": [
{
"phone_type": "home",
"phone_number": "999-999-0909",
"_id": "5888b0bd3c025e54476828dc"
},
{
"phone_type": "home",
"phone_number": "000-000-0000",
"_id": "5888b0bd3c025e54476828db"
}
],
"emails": [
{
"email_address": "Some#them.com",
"_id": "5888b0bd3c025e54476828da"
}
]
}
],
"businesses": [],
"addresses": [],
"phones": [
{
"phone_number": "999-999-9999",
"phone_type": "mobile",
"_id": "5886e37f2ca4542c453431ef"
}
],
"emails": []
}

Answer 1

Mongoose sub documents have special methods to retrieve them:
router
.route('/:ownerId/getcontact/:contactId')
.get(function(req, res) {
Profile.findOne({ owner_id: req.params.ownerId }, function(err, profile) {
if ( err ) {
res.send(err);
}
var contact = profile.contacts.id(req.params.contactId);
res.json(contact);
});
});
See Mongoose Sub Documents.

Answer 2

Another route is through the aggregation framework where you can use the $match, $arrayElemAt and $filter operators to return the data you want.
Consider running the following aggregate operation in your API endpoint implementation:
router.route('/:ownerId/getcontact/:contactId')
.get(function(req, res){
var ownerId = mongoose.Schema.Types.ObjectId(req.params.ownerId),
contactId = mongoose.Schema.Types.ObjectId(req.params.contactId);
Profile.aggregate([
{ "$match": { "owner_id": ownerId } },
{
"$project": {
"contact": {
"$arrayElemAt": [
{
"$filter": {
"input": "$contacts",
"as": "contact",
"cond": { "$eq": ["$$contact._id", contactId] }
}
},
0
]
}
}
}
]).exec(function(err, profile){
if(err) res.send(err);
res.json(profile[0].contact);
})
})