Mongo Unwind child object and Filter - mongodb

Question

Here is the MongoPlayground about this problem
Today I have 2 nested arrays of object:
I have an array of meetings and inside of it an array of invites.
I need to project only the meetings, but with the invites filtered by the PartnerId. So I have many invites to different partners, but when each partner logs to the system, he can only see the invites for him and not the others. In other words, the array Invites will have only invites to it´s PartnerId.
I could get to the project part, but filter the the invites I am lost. Should I use a $filter or $group to another array?
here is what I got so far:
MongoPlayground
db.collection.aggregate([
{
"$match": {
"$nor": [
{
"Meetings": {
"$exists": false
}
},
{
"Meetings": {
"$size": 0.0
}
}
]
}
},
{
"$unwind": {
"path": "$Meetings"
}
},
{
"$project": {
"Meetings": "$Meetings"
}
},
{
"$replaceRoot": {
"newRoot": "$Meetings"
}
}
])
ANSWER that I did...
db.getCollection("ClientProject").aggregate(
[
{
"$match" : {
"$and" : [
{
"PartnerIds" : {
"$in" : [
"5f9b247f0ca60a000232cacf"
]
}
},
{
"$nor" : [
{
"Meetings" : {
"$exists" : false
}
},
{
"Meetings" : {
"$size" : 0.0
}
},
{
"Meetings" : {
"$eq" : null
}
}
]
}
]
}
},
{
"$unwind" : {
"path" : "$Meetings"
}
},
{
"$project" : {
"Meetings" : "$Meetings"
}
},
{
"$replaceRoot" : {
"newRoot" : "$Meetings"
}
},
{
"$addFields" : {
"Invites" : {
"$filter" : {
"input" : "$Invites",
"as" : "invite",
"cond" : {
"$eq" : [
"$$invite.PartnerId",
"5f9b247f0ca60a000232cacf"
]
}
}
}
}
}
],
{
"allowDiskUse" : false
}
);

Answer 1

Using $filter is a good way to achieve your goal, and here is how you can do that:
db.collection.aggregate([
{
"$match": {
"$nor": [
{
"Meetings": {
"$exists": false
}
},
{
"Meetings": {
"$size": 0.0
}
}
]
}
},
{
"$unwind": {
"path": "$Meetings"
}
},
{
"$project": {
"invites": {
"$filter": {
"input": "$Meetings.Invites",
"as": "invite",
"cond": {
"$eq": [
"$$invite.PartnerName",
"Thiago Parceiro "
]
}
}
}
}
}
])