how to get data from database & if data is not available then entered data stored in database in nodejs

how to get data from database & if data is not available then entered data stored in database in nodejs.

I have a code:

router.get('/pincode/:pincode', function (req, res) {
    Pincode.find({
        pincode: req.params.pincode
    }, function (err, pincodes) {
        if (pincodes == '') {
            var pincodeData = new Pincode({
                pincode: req.params.pincode,
                country: req.body.country,
                state: req.body.state,
                district: req.body.district,
                taluka: req.body.taluka,
                city: req.body.city,
                area: req.body.area

            });
            pincodeData.save(function (err, results) {
                if (err) {
                    return err;
                } else {

                    console.log("Got a response: ", results);
                    // console.log("data:"+body);
                }
            });

        }
        res.json(pincodes);
    });
});

via Poonam