Check if sub document is found in $project - node.js

Question

I am trying to find all the trips provided by a company, grouped by the driver of the bus, and check if a given passenger was part of the trip.
Content is an array that can have reference to multiple models: User, Cargo, etc.
I can somewhat achieve my desired result using:
traveled: { $in: [ passengerId, "$content.item" ] },
But i want to confirm that the matched id is indeed a 'User'(passenger). I have tried:
traveled: { $and: [
{ $in: [ passengerId, "$content.item" ] },
{ $in: [ `Passenger`, "$content.kind" ] },
]},
But it also matches if the passed id has a kind of 'Cargo' when there is another content with a kind of 'User' is inside the array.
// Trip
const schema = Schema({
company: { type: Schema.Types.ObjectId, ref: 'Company', required: false },
driver: { type: Schema.Types.ObjectId, ref: 'User', required: true },
description: { type: String, required: true },
....
content: [{
kind: { type: String, required: true },
item: { type: Schema.Types.ObjectId, refPath: 'content.kind', required: true }
}]
});
const Trip = mongoose.model('Trip', schema, 'trips');
Trip.aggregate([
{ $match: { company: companyId } },
{
$project: {
_id: 1,
driver: 1,
description: 1,
traveled: { $in: [ passengerId, "$content.item" ] },
// traveled: { $and: [
// { $in: [ passengerId, "$content.item" ] },
// { $in: [ `Passenger`, "$content.kind" ] },
// ]},
}
},
{
$group : {
_id: "$driver",
content: {
$push: {
_id: "$_id",
description: "$description",
traveled: "$traveled",
}
}
},
}
]).then(console.log).catch(console.log);

Answer 1

There is no $elemMatch operator in $project stage. So to use mimic similar functionality you can create $filter with $size being $gt > 0.
Something like
"traveled":{
"$gt":[
{"$size":{
"$filter":{
"input":"$content",
"as":"c",
"cond":{
"$and":[
{"$eq":["$$c.item",passengerId]},
{"$eq":["$$c.kind","User"]}
]
}
}
}},
0
]
}