Mongoose aggregate match returns empty array - mongodb

Question

I'm working with mongodb aggregations using mongoose and a I'm doubt what am I doing wrong in my application.
Here is my document:
{
"_id": "5bf6fe505ca52c2088c39a45",
"loc": {
"type": "Point",
"coordinates": [
-43.......,
-19......
]
},
"name": "......",
"friendlyName": "....",
"responsibleName": "....",
"countryIdentification": "0000000000",
"categories": [
"5bf43af0f9b41a21e03ef1f9"
]
"created_at": "2018-11-22T19:06:56.912Z",
"__v": 0
}
At the context of my application I need to search documents by GeoJSON, and I execute this search using geoNear. Ok it works fine! But moreover I need to "match" or "filter" specific "categories" in the document. I think it's possible using $match but certainly I'm doing the things wrong. Here is the code:
CompanyModel.aggregate(
[
{
"$geoNear": {
"near": {
"type": "Point",
"coordinates": [pageOptions.loc.lng, pageOptions.loc.lat]
},
"distanceField": "distance",
"spherical": true,
"maxDistance": pageOptions.distance
}
},
{
"$match": {
categories: { "$in": [pageOptions.category] }
}
}
]
).then(data => {
resolve({ statusCode: 200, data: data });
}).catch(err => {
console.log(err);
reject({ statusCode: 500, error: "Error getting documents", err: err });
})
pageOptions:
var pageOptions = {
loc: {
lat: parseFloat(req.query.lat),
lng: parseFloat(req.query.lng)
},
distance: parseInt(req.query.distance) || 10000,
category: req.params.category || ""
}
If I remove $match I get all the documents by location, but I need to filter specific categories... I don't believe that I need to filter it manually, I believe it can be possible with aggregation functions...
So anyone can help me with this mongoose implementation?
Thanks for all help

Answer 1

In MongoDB you need to make sure that data type in your document matches the type in your query. In this case you have a string stored in the database and you're trying to use ObjectId to build the $match stage. To fix that you can use valueOf() operator on pageOptions.category, try:
{
"$match": {
categories: { "$in": [pageOptions.category.valueOf()] }
}
}