Use match to filter result in lookup? MongoDB - mongodb

Question

I quite can't get how should I use the pipeline to filter the resulting array of my look up here's the code
{
"_id" : ObjectId("5d73d591b35c943a201837e2"),
"itemName" : "Vape",
"itemSellingPrice" : "350",
"itemPurchasePrice" : "300",
"itemAveragePurchasePrice" : "133.33333333333334",
"itemBaseUnit" : "Unit 2",
"itemReorderPoint" : "100",
"itemTotalQuantity" : "300",
"itemSumQuantity" : "500",
"itemLocation" : "1",
"itemSubLocation" : "sub loc 1",
"itemDateCreated" : ISODate("2019-09-07T16:06:41.521Z"),
"itemID" : 88,
"__v" : 0,
"salesData" : [
{
"_id" : ObjectId("5d73e23ed8422d2ba42049b4"),
"salesOrderCustomerName" : "Manong Puring",
"salesOrderInvoiceNumber" : "1123",
"salesOrderAddress" : "Jan lang",
"salesOrderPaymentStatus" : "Open",
"salesOrderTotalPaid" : "0",
"salesOrderTotalAmount" : "2800",
"salesOrderDiscrepancyAmount" : "2800",
"salesOrderItemList" : [
{
"_id" : ObjectId("5d73e23ed8422d2ba42049b5"),
"salesOrderSelectedItem" : "Vape",
"salesOrderAverage" : "133.33333333333334",
"salesOrderNewPrice" : "350",
"salesOrderPurchasePrice" : "300",
"salesOrderQuantity" : "8",
"salesOrderSubTotal" : "2800"
}
],
"salesOrderDateCreated" : ISODate("2019-09-07T16:00:00.000Z"),
"salesOrderSubLocation" : "sub loc 1",
"salesOrderLocation" : "1",
"salesOrderID" : 62,
"__v" : 0
},
{
"_id" : ObjectId("5d73e37164ade31b40775038"),
"salesOrderCustomerName" : "Manong Puring",
"salesOrderInvoiceNumber" : "123",
"salesOrderAddress" : "Jan lang",
"salesOrderPaymentStatus" : "Open",
"salesOrderTotalPaid" : "0",
"salesOrderTotalAmount" : "350",
"salesOrderDiscrepancyAmount" : "350",
"salesOrderItemList" : [
{
"_id" : ObjectId("5d73e37164ade31b40775039"),
"salesOrderSelectedItem" : "Vape",
"salesOrderAverage" : "133.33333333333334",
"salesOrderNewPrice" : "350",
"salesOrderPurchasePrice" : "300",
"salesOrderQuantity" : "1",
"salesOrderSubTotal" : "350"
}
],
"salesOrderDateCreated" : ISODate("2019-09-07T16:00:00.000Z"),
"salesOrderSubLocation" : "sub loc 2",
"salesOrderLocation" : "1",
"salesOrderID" : 63,
"__v" : 0
}
]
}
I only want to get salesData with salesOrderSubLocation: "sub loc 1"
but it is showing data with sub loc 2 also. Searched for a while but can't find an exact problem with mine.
here's my query
db.getCollection('itemmodels').aggregate(
{ '$match': { itemName: 'Vape' } },
{ '$lookup':
{
from: 'itemmodels',
let: { "itemName": "$itemName" },
pipeline: [
{ $match: {
"salesOrderSubLocation": "sub loc 1",
"salesOrderItemList.salesOrderSelectedItem": "$$itemName"
}
}
],
as: 'salesData'
}
})
any idea guys? I don't want to filter the result in the front end because it my cause some problems with tons of data in the future.