Mongoose: Find() return document with the the object that contains the value

I found a way to return the data as I wish, by using aggregate with $unwind.

Cities.aggregate([{
        $unwind: '$states'
    },
    {
        $unwind: '$states.cities'
    },
    {
        $match: {
            'states.cities.name': {$regex: city, $options: "i"}
        }
    }

    ],
        function (error, data) {
            return res.json(data);
        })