Flter mongodb database using mongoose nodejs - node.js

Question

I need to filter some users according to some fixed criteria. I have a user collection and a talent collection. The talent collection holds the reference to a master category collection.
What I need is to filter these users according to the category in the talent collection and some keys from the user collection.
For example I need to search for a user whose gender is 'male' and education 'BTech' and will have talents as a programmer and tester
my user collection is like,
{
"_id": "5f1939239bd35429ac9cd78f",
"isOtpVerified": "false",
"role": "user",
"adminApproved": 1,
"status": 0,
"languages": "Malayalam, Tamil, Telugu, Kannada",
"name": "Test user",
"email": "test#email.com",
"phone": "1234567890",
"otp": "480623",
"uid": 100015,
"bio": "Short description from user",
"dob": "1951-09-07T00:00:00.000Z",
"gender": "Male",
"education": "Btech",
"bodyType": "",
"complexion": "",
"height": "",
"weight": "",
"requests": [],
"location": {
"place": "place",
"state": "state",
"country": "country"
},
"image": {
"avatar": "5f1939239bd35429ac9cd78f_avatar.jpeg",
"fullsize": "5f1939239bd35429ac9cd78f_fullsize.png",
"head_shot": "5f1939239bd35429ac9cd78f_head_shot.jpeg",
"left_profile": "5f1939239bd35429ac9cd78f_left_profile.png",
"right_profile": "5f1939239bd35429ac9cd78f_right_profile.png"
},
"__v": 42,
"createdAt": "2020-07-23T07:15:47.387Z",
"updatedAt": "2020-08-18T18:54:22.272Z",
}
Talent collection
[
{
"_id": "5f38efef179aca47a0089667",
"userId": "5f1939239bd35429ac9cd78f",
"level": "5",
"chars": {
"type": "Fresher",
},
"category": "5f19357b50bcf9158c6be572",
"media": [],
"createdAt": "2020-08-16T08:35:59.692Z",
"updatedAt": "2020-08-16T08:35:59.692Z",
"__v": 0
},
{
"_id": "5f3b7e6f7e322948ace30a2c",
"userId": "5f1939239bd35429ac9cd78f",
"level": "3",
"chars": {
"type": "Fresher",
},
"category": "5f19359250bcf9158c6be573",
"media": [
{
"adminApproved": 0,
"status": 0,
"_id": "5f3c22573065f84a48e04a14",
"file": "id=5f1939239bd35429ac9cd78f&dir=test&img=5f1939239bd35429ac9cd78f_image_undefined.jpeg",
"description": "test",
"fileType": "image",
"caption": "test file"
},
{
"adminApproved": 0,
"status": 0,
"_id": "5f3c2d7a8c7f8336b0bfced2",
"file": "id=5f1939239bd35429ac9cd78f&dir=test&img=5f1939239bd35429ac9cd78f_image_1.jpeg",
"description": "this is a demo poster for testing",
"fileType": "image",
"caption": "A Test Poster"
}
],
"createdAt": "2020-08-18T07:08:31.532Z",
"updatedAt": "2020-08-18T19:35:22.899Z",
"__v": 2
}
]
And the category in the above document is a separate one populated to this. the category collection as,
[
{
"_id": "5f19359250bcf9158c6be573",
"status": true,
"title": "Testing",
"description": "Application tester",
"code": "test",
"characteristics": [],
"createdAt": "2020-07-23T07:00:34.221Z",
"updatedAt": "2020-07-23T07:00:34.221Z",
"__v": 0
},
{
"status": true,
"_id": "5f29829a705b4e648c28bc88",
"title": "Designer",
"description": "UI UX Designer",
"code": "uiux",
"createdAt": "2020-08-04T15:45:30.125Z",
"updatedAt": "2020-08-04T15:45:30.125Z",
"__v": 0
},
{
"_id": "5f19357b50bcf9158c6be572",
"status": true,
"title": "programming",
"description": "Java programmer",
"code": "program",
"createdAt": "2020-07-23T07:00:11.137Z",
"updatedAt": "2020-07-23T07:00:11.137Z",
"__v": 0
}
]
So my filter terms will be;
{
categories: ["5f19359250bcf9158c6be573", "5f19357b50bcf9158c6be572"],
minAge: 18,
maxAge: 25,
minHeight: 5,
maxHeight: 6,
minWeight: 50,
maxWeight: 80,
complexion: "white",
gender: "male",
}
And the expected result will be a user have both the above talents and followed conditions,
{
users: { ..User details.. },
medias: { ...medias from the matching talents.. }
}

Answer 1

If there are two collections you need to join them either by primary key or _id with foriegn fields and you can use $lookup with $match to filter down.
Documentation

Answer 2

You need to use $lookup with pipeline,
$match you condition for category match
$lookup to join users collection
$match conditions for users collections fields
$match exclude documents that don't found matching users of criteria passed in conditions
db.talents.aggregate([
{
$match: {
category: { $in: ["5f19359250bcf9158c6be573", "5f19357b50bcf9158c6be572"] }
}
},
{
$lookup: {
from: "users",
as: "users",
let: { userId: "$userId" },
pipeline: [
{
$match: {
$expr: {
$and: [
{ $eq: ["$$userId", "$_id"] },
{ $eq: ["$gender", "Male"] },
{ $eq: ["$education", "Btech"] }
// ... add you other match criteria here
]
}
}
}
]
}
},
{ $match: { users: { $ne: [] } } }
])
Playground