How to create an array containing arrays on MongoDB - mongodb

Question

I'm trying to make a query to mongodb. I want to get an array containing [location, status] of every document.
This is how my collection looks like
{
"_id": 1,
"status": "OPEN",
"location": "Costa Rica",
"type": "virtual store"
},
{
"_id": 2,
"status": "CLOSED",
"location": "El Salvador"
"type": "virtual store"
},
{
"_id": 3,
"status": "OPEN",
"location": "Mexico",
"type": "physical store"
},
{
"_id": 4,
"status": "CLOSED",
"location": "Nicaragua",
"type": "physical store"
}
I made a query, using the aggregate framework, trying to get all documents that match that specific type of store.
{
{'$match': {
'type': { '$eq': "physical store"}
}
}
What I want is something like this:
{
{
'stores': [
["Mexico", "OPEN"],
["Nicaragua", "CLOSED"]
]
},
}
I tried with the $push but couldn't make it.
Could someone please guide me on how to do it.

Answer 1

Since { $push: ["$location", "$status"] } would give you the error The $push accumulator is a unary operator. You would have to work around it a bit by passing to it a single object that output your desired array. One way to do it would be:
[
{
"$match": {
"type": {
"$eq": "physical store"
}
}
},
{
"$group": {
"_id": null,
"stores": {
"$push": {
"$slice": [["$location", "$status"], 2]
}
}
}
}
]

Answer 2

If the given documents are not sub-documents, then below is the approach:
db.collection.find({
type: {
$eq: "physical store"
}
},
{
location: 1,
status: 1
})
MongoPlayGround link for the above
If, they are the part of a field (means they are sub-documents), then below is the approach:
db.collection.aggregate([
{
$project: {
stores: {
$filter: {
input: "$stores",
as: "store",
cond: {
$eq: [
"$$store.type",
"physical store"
]
}
}
}
}
},
{
$unwind: "$stores"
},
{
$project: {
location: "$stores.location",
status: "$stores.status",
_id: "$stores._id"
}
}
])
MongoPlayGround link for the above