Make the sum of booleans as integers with MongoDB - arrays

Question

I'm trying to sum booleans (where true means 1 and false -1) in an array for each document in my collection and then sort it.
I'm using MongoDB aggregation pipeline with $addFields, $sum and $cond.
Here's the playground : https://play.db-ai.co/m/XQLKqbkkgAABTFVm
The pipeline :
[
{
"$addFields": {
"score": {
"$sum": {
"$cond": [
"$votes.value",
1,
-1
]
}
}
}
},
{
"$sort": {
"score": -1
}
}
]
The collection :
[
{
"votes": [
{
"value": true
},
{
"value": true
},
{
"value": true
},
{
"value": false
}
]
},
{
"votes": [
{
"value": true
},
{
"value": true
},
{
"value": false
},
{
"value": false
}
]
}
]
Actual results :
[
{
"_id": ObjectId("000000000000000000000000"),
"votes": [
{
"value": true
},
{
"value": true
},
{
"value": true
},
{
"value": false
}
],
"score": 1
},
{
"_id": ObjectId("000000000000000000000001"),
"votes": [
{
"value": true
},
{
"value": true
},
{
"value": false
},
{
"value": false
}
],
"score": 1
}
]
What I want :
[{
"_id": ObjectId("000000000000000000000000"),
"votes": [
{
"value": true
},
{
"value": true
},
{
"value": true
},
{
"value": false
}
],
"score": 2
}, {
"_id": ObjectId("000000000000000000000001"),
"votes": [
{
"value": true
},
{
"value": true
},
{
"value": false
},
{
"value": false
}
],
"score": 0
}]

Answer 1

I got it to work by unwinding the array and then grouping by _id again.
See Playground: https://play.db-ai.co/m/XQMFlZAtYAABLHtL
[
{
"$unwind": {
"path": "$votes"
}
},
{
"$group": {
"_id": "$_id",
"votes": {
"$push": "$votes"
},
"score": {
"$sum": {
"$cond": [
"$votes.value",
1,
-1
]
}
}
}
},
{
"$sort": {
"score": -1
}
}
]

Answer 2

To solve my problem I used $map multiple times. The solution of #Plancke is working but I had issues using a $match afterwards (it was always giving no results).
[
{
$addFields: {
scoresInBoolean: {
$map: {
input: '$votes',
as: 'vote',
in: '$$vote.value',
},
},
},
}, {
$addFields: {
scoresInInteger: {
$map: {
input: '$scoresInBoolean',
as: 'scoreInBoolean',
in: {
$cond: [
'$$scoreInBoolean',
1,
-1,
],
},
},
},
},
}, {
$addFields: {
score: {
$sum: '$scoresInInteger',
},
},
}
]