I have the following code:
const array = ['a', 'b', 'c']
await collection.aggregate([
{
$match: {
codes: { $in: array }
}
},
{
$addFields: { matchedField: "codes.$" } // <--- does not work
},
]).toArray();
I need to append the matched element from within array to the returned results. Is it possible to do that?
My collection contains documents with the following scheme:
{
"color": "red",
"codes": [ "b" ]
}
I need the aggregation directive to return this:
{
"color": "red",
"codes": [ "b" ],
"matchedField": "b",
}
$filter
db.collection.aggregate([
{
"$match": {
"codes": {
"$in": [
"a",
"b",
"c"
]
}
}
},
{
"$set": {
codes: {
$filter: {
input: "$codes",
as: "c",
cond: {
$in: [
"$$c",
[
"a",
"b",
"c"
]
]
}
}
}
}
}
])
$setIntersection
db.collection.aggregate([
{
"$match": {
"codes": {
"$in": [
"a",
"b",
"c"
]
}
}
},
{
"$set": {
codes: {
$setIntersection: [
"$codes",
[
"a",
"b",
"c"
]
]
}
}
}
])