使用距离过滤mongodb文档

Question

我很难使用用户的坐标（最大距离）来过滤文档。

我的请求如下：

app.post('/item', checkAuth, function(request, response) {

    var location = request.body.location;
    var distance = request.body.distance;

    Item.find( {  "location": {
        $near: {   $geometry: {  type: "Point",
                               coordinates: [location.longitude, location.latitude] },
                               $maxDistance: distance
                              
               }
    } }, function(err, items) {
        if (err) {
            response.status(500).send({error: err});
        } else {
            response.send({items : items,
                           message: 'Fetching items successful'
                          });
        }
    });
});