Nested output by group in mongoDB - mongodb

Question

I have a collection like this.
let Movies= [
{year: '2000', language: 'English', genre: 'Romance' , name: 'A beautiful day'},
{year: '2000', language: 'English', genre: 'Action' , name: 'A Dangerous day'},
{year: '2000', language: 'French', genre: 'Romance' , name: 'someromancename'},
{year: '2000', language: 'French', genre: 'Action' , name: 'someactionname'},]
I need to get a output in group format which may look something like this:
{
"2000" : {
"English": {
"Romance": [{
"name":"A beautiful day"
//other fields
}]
"Action": [{
"name":"A dangerous day"
}]
},
"French": {
"Romance": [{
"name":"Some Romance Name"
}]
"Action": [{
"name":"Some Action Name"
}]
},
}
}
I have tried using aggregation but not able to get the exact query as I am new to MongoDB. This is what I tried to do but the expected result is not achieved.
db.getCollection('Movies').aggregate([
{$group: {_id: {"year" : "$year",
"language": "$language" ,
"genre": "$genre" ,
},
"movies": {"$push": "$$ROOT"}
}
},
{$group: {_id: "$_id.year",
"movies": {"$push": {
"language": "$_id.language",
"genre": "$_id.genre" ,
"movies": "$movies"
}}
}
},
])

Answer 1

You can try,
$group by year, language and genre, and make array of movies name in movies
$group by year and language and make array of with genre in k and v format
$group by year and make array of language after converting above genre array to object using $arrayToObject
convert language array to object using $arrayToObject, convert year with languages object to object using $arrayToObject and replace that object to root using $replaceRoot
db.getCollection('Movies').aggregate([
{
$group: {
_id: {
"year": "$year",
"language": "$language",
"genre": "$genre"
},
"movies": { "$push": { name: "$name" } }
}
},
{
$group: {
_id: {
year: "$_id.year",
language: "$_id.language"
},
"movies": {
"$push": {
k: "$_id.genre",
v: "$movies"
}
}
}
},
{
$group: {
_id: "$_id.year",
movies: {
$push: {
k: "$_id.language",
v: { $arrayToObject: "$movies" }
}
}
}
},
{
$replaceRoot: {
newRoot: {
$arrayToObject: [[
{
k: "$_id",
v: { $arrayToObject: "$movies" }
}
]]
}
}
}
])
Playground