MongoDB aggregate entries by month

mongodb-monthly.js

db.getCollection('users').aggregate(
[
    {
        $group:
        {
            _id:
            {
                month: { $month: "$created" }, 
                year: { $year: "$created" }
            }, 
            count: { $sum:1 },
            date: { $first: "$created" }
        }
    },
    {
        $project:
        {
            date:
            {
                $dateToString: { format: "%Y-%m", date: "$date" }
            },
            count: 1,
            _id: 0
        }
    },
    
    { $sort: {
        'date': -1, 
    }}
])