Removing nested field in app_metadata

gistfile1.txt

function (user, context, callback) {
    var req = require("request");
    var baseURI = "https://[tenant name].auth0.com/api/v2/";
    var id = user.user_id;

    var bname = user && user.app_metadata && user.app_metadata.bname ? user.app_metadata.bname : null;
   // console.log(bname);
   if (bname!==null) {
        var url = `${baseURI}users/${id}`;
        console.log(url);
        var headers = {
            "Authorization": `Bearer ${auth0.accessToken}`
        };
        var body = {
            "app_metadata": {
                "bname": null
            }
        };
        req.patch({
            url: url,
            headers: headers,
            json: body
        }, function (err, res, context) {
            if (err) {
                console.log(JSON.stringify(err));
            }
            console.log(JSON.stringify(res));
        });

    }

    callback(null, user, context);
}