mongoQuery.js

const query = [
        {
            "$match": {
                "$and": [
                    {
                        "death.date": {
                            "$exists": false
                        }
                    }
                ]
            }
        },
        {
            "$project": {
                "age": {"$subtract": [{"$year": new Date()}, {"$year": "$birthDateMongo"}]},
                "sex": 1
            }
        },
        {
            "$group": {
                "_id": {"age": "$age", "sex": "$sex"},
                "count": {"$sum": 1}
            }
        }
    ]