Group by not working using populate in mongoose - node.js

Question

I have trouble to fill the fields of group in .populate({}), I tried many times but I could not understand the problem:
Company.find({
_id: req.body.idCompany,
})
.populate({
path: 'listAgencys',
model: 'Agency',
match: {
idClient: req.body.idClient,
createdAt: {
$gte: new Date(req.body.startDate),
$lte: new Date(req.body.endDate)
}
},
group: {
_id: {
subscriptionType: '$subscriptionName',
year: { $year: '$createdAt' },
month: { $month: '$createdAt' },
month: {
$let: {
vars: {
monthsInString: [, 'Jan.', 'Fev.', 'Mars', ......]
},
in: {
$arrayElemAt: ['$$monthsInString', { $month: '$createdAt' }]
}
}
}
},
countLines: { $sum: 1 },
} ,
group: {
_id: "$_id.subscriptionType",
info: {
$push: {
year: "$_id.year",
month: "$_id.month",
allLines: "$countLines",
}
},
}
})
.exec();
SCHEMAS:
const companySchema = new mongoose.Schema({
_id: mongoose.Schema.Types.ObjectId,
name: {
type: String,
trim: true,
},
listAgencys: [
{
type: mongoose.Schema.Types.ObjectId,
ref: "Agency",
}
]
});
module.exports = mongoose.model("Company", companySchema);
--
const agencySchema = new mongoose.Schema({
_id: mongoose.Schema.Types.ObjectId,
idClient: {
type: Number,
trim: true,
//unique: true,
},
adress: {
type: String,
trim: true,
lowercase: true,
},
createdAt: {
type: Date,
default: Date.now()
},
listOfSubscribers: [{
numberSubscriber: {
type: Number,
},
numberPhone: {
type: Number,
},
subscriptionName: {
type: String
},
}],
});
module.exports = mongoose.model("Agency", agencySchema);
Example of parameters;
{
"idCompany": "5c71ba1c1376b034f8dbceb6",
"startDate":"2019-02-23",
"endDate":"2019-03-31",
"idClient" : "021378009"
}
I want to display the number of subscribers per month and subscriptionType according to idAgency and idCompany that will be passed in parameter.
Edit1 with aggregate:
Company.aggregate(
[
{ $unwind: "$listAgencys" },
{
$match: {
_id: req.body.idCompany,
idClient: req.body.idClient,
createdAt: {
"istAgencys.createdAt": {
$gte: new Date(req.body.startDate),
$lte: new Date(req.body.endDate)
}
}
},
{
$group: {
_id: {
subscriptionType: '$listAgencys.subscriptionName',
year: { $year: '$createdAt' },
month: { $month: '$createdAt' },
month: {
$let: {
vars: {
monthsInString: [, 'Jan.', 'Fev.', 'Mars', ......]
},
in: {
$arrayElemAt: ['$$monthsInString', { $month: '$createdAt' }]
}
}
}
}
countLines: { $sum: 1 },
} ,
{
$group: {
_id: "$_id.subscriptionType",
info: {
$push: {
year: "$_id.year",
month: "$_id.month",
allLines: "$countLines",
}
}
}
}
])
Result of edit1:
{
success: true,
datalines : []
}
Example of output:
{
"success": true,
"datalines": [
{
"idClient": 0213400892124
{
"_id": {
"subscriptionType": "ADL",
"year": 2019,
"month" : "Fev."
},
"allLines": 3,
},
{
"_id": {
"subscriptionType": "Lines",
"year": 2019,
"month" : "Jan."
},
"allLines": 10,
},
{
"_id": {
"subscriptionType": "Others",
"year": 2019,
"month" : "Mars"
},
"allLines": 35,
}
},
{
"idClient": 78450012365
.........
}
]
}
thank you in advance,