How can I weight each MongoDB search query differently?

Question

I have a MongoDB collection that looks something like this:

{
    "name": "McAllister's Deli",
    "menu": [
        {"sandwich": 4},
        {"spud": 3},
        {"salad": 5},
        {"cookie":2}
    ],
    "reviews": 45
}

I would like to rank these restaurants based on the types of food they have and the number of reviews. For instance, if someone is looking for cookie and sandwich , McAllister's Deli would return a ranking of say 19.28 by taking (cookie * sandwich * reviews) / menuItems . Is there a way to optimize my query to take this ranking into account?

Edit: Since it was asked in a comment, I am currently using the Dart driver, but I am familiar with the Mongo shell and can translate a shell query to a query my driver understands.

Answer 1

db.rest.aggregate([{
    $project: { 
        _id: 1,
        sandwich: { $arrayElemAt: [ '$menu.sandwich', 0]},
        cookie: { $arrayElemAt: [ '$menu.cookie', 0]},
        menuItems: {$size: '$menu'}
    }
},{
    $project: { 
        _id: 1,
        rank: { $divide: [{ $add: ['$sandwich', '$cookie']}, '$menuItems' ]}
    }
}

])

probably can be combined. $project is separated for clearance.