Proper Mongoose Subdocument Relation

I have a model

const userSchema = Schema({
username: String
})

const invitationSchema = Schema({
decision: String,
user: {
type: Schema.ObjectId,
ref: 'User'
}
})

const groupSchema = Schema({
name: String,
invitations: [{
type: Schema.ObjectId,
ref: 'Invitation'
}]
})


So the basic model looks like

group {
name
invitations [
user {
username
}
]
}


As user i would like to get all groups that i have invitations for

const user = getContextUser()
Group.find({
'invitations.user': user._id
})


But it doesn't seem to work, i could use a property group referring to Group schema in Invitation model, but i want the good way approach

Group

Invitation

How to i get all groups that user have invitations for

Don't look at this below, this is my actual model representation in json, just in case

// GROUP
{
"_id": ObjectId("5b3901dd9a8c0e6790af4ee8"),
"image": {
"filename": "8547aa2a-d16c-4da7-8d51-6c9bf8038037.jpg",
"width": 236,
"height": 156
},
"geolocation": {
"coordinates": [-152.1997, -24.7718],
"type": "Point"
},
"invitations": [
ObjectId("5b3901dd9a8c0e6790af4eea"),
ObjectId("5b3901dd9a8c0e6790af4eeb"),
ObjectId("5b3901dd9a8c0e6790af4eec"),
ObjectId("5b3901dd9a8c0e6790af4eed"),
ObjectId("5b3901dd9a8c0e6790af4eee"),
ObjectId("5b3901dd9a8c0e6790af4eef"),
ObjectId("5b3901dd9a8c0e6790af4ef0")
],
"messages": ,
"title": "id in magnam",
"description": "Cupiditate doloremque sunt placeat beatae et ex rerum nisi voluptate. Aliquam hic voluptas quas iure assumenda rerum aut. Quisquam vero beatae odit aut ut quod magnam.",
"created_at": ISODate("2018-07-01T16:31:25.237Z"),
"created_by": ObjectId("5b3901dc9a8c0e6790af4ee1"),
"color": "#347303",
"require_people_decision": true,
"is_public": true,
"start_date": ISODate("2019-03-18T20:05:03.116Z"),
"end_date": ISODate("2019-03-18T20:05:03.116Z"),
"location": "25498 Berniece Prairie",
"__v": 1
}

// INVITATION
{
"_id": ObjectId("5b3901dd9a8c0e6790af4eea"),
"created_at": ISODate("2018-07-01T16:31:25.348Z"),
"have_seen": false,
"user": ObjectId("5b3901dc9a8c0e6790af4ee0"),
"__v": 0
}

// USER
{
"_id": ObjectId("5b3901dc9a8c0e6790af4ee0"),
"avatar": {
"filename": "d438befb-2ea3-4582-b6bf-b8dd3b9bcf66.jpeg",
"width": 200,
"height": 200
},
"phone": "5556106679",
"password": "$2b$10$mbx9Yhj5mAKyVxwmxcumaepXYkCTiF/9VM2KJRARZkPOVN300pKc.",
"version": 1,
"friends": ,
"__v": 0
}

1 Answer
1

You can try below aggregation

Group.aggregate([
{ "$lookup": {
"from": Invitations.collection.name,
"let": { "invitations": "$invitations" },
"pipeline": [
{ "$match": { "$expr": { "$in": [ "$_id", "$$invitations" ] } } }
],
"as": "invitations"
}},
{ "$match": { "invitations.user": user._id } }
])


or this

Group.aggregate([
{ "$lookup": {
"from": Invitations.collection.name,
"let": { "invitations": "$invitations" },
"pipeline": [
{ "$match": {
"user": user._id,
"$expr": { "$in": [ "$_id", "$$invitations" ] }
}}
],
"as": "invitations"
}},
{ "$match": { "invitations.user": user._id } }
])


And the last one which I think is the best option to start with User collection

User

User.aggregate([
{ "$match": { "_id": user._id }},
{ "$lookup": {
"from": Groups.collection.name,
"let": { "userId": "$_id" },
"pipeline": [
{ "$match": { "$expr": { "$eq": [ "$created_by", "$$userId" ] }}}
],
"as": "groups"
}}
])


Invitations.collection.name

'Invitation'

invitations

Invitation

invitations

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