Conditionally apply and condition in MongoDB

Question

I am trying to fetch data conditionally based on parameter passed.

Parameters are 'room' and 'area'

if room is not equal to 'any', I want to add condition in filter for room.
if area is not equal to 'all', I want to add condition in filter for area.

exports.get_property_search = function (req, res) {
    var filter = [];
    if (req.params.area != "all")
        filter.push({ "area": req.params.area });
    if (req.params.room != "any")
        filter.push({ "roomQty": req.params.room });

    AddProperty.find({
        $expr:
        {
            $cond:
            {
                if: filter != [],
                then: {
                    $and: filter
                },
                else: {

                }
            }
        }
    }, function (err, addProperty) {
        if (err)
            res.send({ code: '500', message: err });
        res.send({ code: '200', data: addProperty });
    });
};

But, this condition is not working and all returning all the data without any filter.

Answer 1

You are going with the wrong syntax here. And this can be done using simple javascript code instead of using aggregation operator.

let filter = {}
  if (req.params.area !== "all") {
    filter.area = req.params.area
  }
  if (req.params.room !== "any") {
    filter.roomQty = req.params.room
  }

  AddProperty.find(filter).then((data) => {
    console.log(data)
  })