Removing Dynamic Fields by Association in MongoDB Aggregation - node.js

Question

I'm trying to display a MongoDB aggregation result via react chartjs. in aggregation, I can remove one field whose value is static via the set operator. is there a way to remove a second field by an association whose value is dynamic? in the example below, {"A": "N"} denotes the field that is readily removed by the set operator, whereas {"A_count":1} denotes the corresponding dynamic field that I am trying to remove.
starting aggregation output
[{
"_id":"Fubar",
"A_set":[{"A":"Y"},{"A":"N"}],
"A_count_set":[{"A_count":0},{"A_count":1}]
}]
set operation for static field removal
{$set: {
A_set: {
$filter: {
input: "$A_set",
as: "x",
cond: { "$ne": [ "$$x", {"A":"N"}] }
}
}
}}
current aggregation output
[{
"_id":"Fubar",
"A_set":[{"A":"Y"}],
"A_count_set":[{"A_count":0},{"A_count":1}]
}]
target aggregation output
[{
"_id":"Fubar",
"A_set":[{"A":"Y"}],
"A_count_set":[{"A_count":0}]
}]

Answer 1

$project merge two array with the same position
$set filter array
$addFields recover the original array
$project remove the merge array
aggregate
db.collection.aggregate([
{
$project: {
anotherValue: {
$map: {
input: {
$range: [
0,
{
$size: "$A_set"
}
]
},
as: "idx",
in: {
$mergeObjects: [
{
$arrayElemAt: [
"$A_set",
"$$idx"
]
},
{
$arrayElemAt: [
"$A_count_set",
"$$idx"
]
}
]
}
}
}
}
},
{
$set: {
anotherValue: {
$filter: {
input: "$anotherValue",
as: "x",
cond: {
"$ne": [
"$$x.A",
"N"
]
}
}
}
}
},
{
$addFields: {
"A_set": {
$map: {
input: "$anotherValue",
as: "a",
in: {
"A": "$$a.A"
}
}
},
"A_count_set": {
$map: {
input: "$anotherValue",
as: "a",
in: {
"A_count": "$$a.A_count"
}
}
}
}
},
{
"$project": {
"anotherValue": 0
}
}
])
mongoplayground