MongoDB aggregation group by ID then code - node.js

Question

I have this collection:
[{
"_id": "5c378eecd11e570240a9b0ac",
"userID": "1",
"isActive": "Active",
"areaCode": "A-1",
"__v": 0
},
{
"_id": "5c378eecd11e570240a9b0bb",
"userID": "1",
"isActive": "Active",
"areaCode": "A-2",
"__v": 0
},
{
"_id": "5c378eecd11e570240a9b0c5",
"userID": "2",
"isActive": "Active",
"areaCode": "A-1",
"__v": 0
}]
Need help in grouping the results by user ID then the area code using aggregation but I'm not getting the desired output. Here's what I've tried:
AreaCodes.aggregate([
{
'$match': { '$and': [
{ 'isActive': 'Active' },
{ 'userID': { '$exists': true } }
]
}
},
{
'$group': {
'_id': {
'userID': '$userID'
},
'entries': {
'$push': {
'areaCode': '$areaCode'
}
}
}
},
{
'$group': {
'_id': '$_id.userID',
'areaCodes': {
'$push': {
'areaCode': '$entries'
}
}
}
},
{
'$project': {
'_id': 0,
'userID': '$_id',
'areaCodes': '$areaCodes'
}
}
])
Which returns the following:
[
{
"userID": "1",
"areaCodes": [
{
"areaCode": [
{
"areaCode": "A-1"
},
{
"areaCode": "A-2"
}
]
}
]
},
{
"userID": "2",
"areaCodes": [
{
"areaCode": [
{
"areaCode": "A-1"
}
]
}
]
}
]
My desired output would be to remove the excess areaCode objects and group them inside an array for each user like:
[
{
"userID": "1",
"areaCodes": ["A-1", "A-2"]
},
{
"userID": "2",
"areaCodes": ["A-1"]
}
]
How to achieve this format? Thanks.

Answer 1

How about:
db.collection.aggregate([
{
$match: {
$and: [{ "isActive": "Active" }, {"userID": {"$exists": true}}]
}
},
{
$group: {
_id: '$userID',
areaCodes: {$addToSet: "$areaCode"}
}
},
{
$project: {
_id: 0,
userID: "$_id",
areaCodes: 1
}
}
])
As you can see on this playgeound example.
If you just want the matching areaCodes, you can simply use $addToSet.