How to retrieve specific queried array collections in MongoDB using NodeJS - node.js

Question

I've just tried MongoDB & NodeJS and having issue in finding specific array collections using Nodejs.
Here's the the collections I have :
{
"_id": ObjectId("552aa4da6e25e57ebde7ac6f"),
"username": "blablabla",
"email": "xxx#gmail.com",
"password": "Dummy Trip",
"itinerary": [
{
"_id": ObjectId("552c109adb616795044a919e"),
"title": "test-0",
"desc": "test-0-desc"
},
{
"_id": ObjectId("552c10b0db616795044a91a0"),
"title": "test-1",
"desc": "test-1-desc"
},
{
"_id": ObjectId("552c1128db616795044a91a1"),
"title": "test-2",
"desc": "test-2-desc"
}
]
}
So I need to find the array of itinerary that has objecId of "552c109adb616795044a919e"
In MongoDB terminal I use findOne command & positional $ operator and it works as expected, showing only the array I search for.
Command :
db.user.findOne({ "itinerary._id" : ObjectId("552c109adb616795044a919e") }, {"itinerary.$" : 1})
Result :
{
"_id" : ObjectId("552aa4da6e25e57ebde7ac6f"),
"itinerary" : [
{
"_id" : ObjectId("552c109adb616795044a919e"),
"title" : "test-0",
"desc" : "test-0-desc"
}
]}
But why when I tried to implement it in NodeJS, it shows all records instead of the specific array I search.
Here's my NodeJS :
var userCollection = db.get('user');
userCollection.findOne({ "itinerary._id" : new ObjectID("552c109adb616795044a919e") }, {"itinerary.$" : 1},function(e,userDocs){
console.log(userDocs);
});
NodeJS Result (Showing all results) :
{
_id: 552aa4da6e25e57ebde7ac6f,
username: 'blablabla',
email: 'xxx#gmail.com',
password: 'Dummy Trip',
itinerary: [
{
_id: 552c109adb616795044a919e,
title: 'test-0',
desc: 'test-0-desc'
},
{
_id: 552c10b0db616795044a91a0,
title: 'test-1',
desc: 'test-1-desc'
},
{
_id: 552c1128db616795044a91a1,
title: 'test-2',
desc: 'test-2-desc'
}
]
}
Did I miss something here ?
Note :
I'm using Node MongoDB native driver
Thanks in advance :)

Answer 1

I am assuming your itinerary is an array. then you will have to use $elemMatch in mongodb.More details on elemMatch.
You can try something like.
var userCollection = db.get('user');
userCollection.findOne({ "itinerary": { $elemMatch: {_id: new ObjectID("552c109adb616795044a919e")}}}, {"itinerary.$" : 1},function(e,userDocs){
console.log(userDocs);
});
Also i think for matching object id you can use mongoose.Types.ObjectId("552c109adb616795044a919e")