Display object list with a parameter on Mongoose - mongodb

Question

I have a find query that returns me a list of objects:
{
"_id": "5fb94fda487b9348c4291450",
"name": [
{
"NewConfirmed": 642686,
"TotalConfirmed": 49315431,
"NewDeaths": 9555,
"TotalDeaths": 1242785,
"NewRecovered": 288131,
"TotalRecovered": 32473892
},
{
"NewConfirmed": 116262,
"TotalConfirmed": 6014461,
"NewDeaths": 4640,
"TotalDeaths": 371913,
"NewRecovered": 77575,
"TotalRecovered": 2492884
},
{
...
Its all fine but I'm trying to make a new query with a status parameter with the value NewConfirmed or TotalConfirmed or NewDeaths to display only that specific field. So the endpoints would look like /something/status/:status.
I already tried an aggregation with filter and a simple find but still havent figured nothing out.
Anyone has any idea?

Answer 1

First of all, you need a query with this estructure:
db.collection.aggregate([
{
/**Your match object*/
},
{
"$project": {
"YourStatus": {
"$first": "$name.YourStatus"
}
}
}
])
Example here.
Using mongoose you need to create the object query in this way:
var query = {}
query[status] = {"$first": "$name."+status}
And do the mongoose query replacing the object by query object.
var aggregate = await model.aggregate([
{
//Your $match stage here
},
{
"$project": query
}
])
Also, I've tested in local but my mongo version (I think) doesn't recognize $first so I've used $arrayElemAt. According to mongo docs is the same as $first.
var status = "NewConfirmed"
var query = {}
query[status] = { $arrayElemAt: ["$name."+status, 0]}
Also you can add _id: 0 into $project aggregate to not return this field.
var query = {_id:0} //Here add _id: 0 to project object
query[status] = { $arrayElemAt: ["$name."+status, 0]} //And the rest of the stage