node.js - how to reconnect mongoose default connection? -

my app.js contains,

 exports.getdatabaseconnection = function (dbname, uname, psw) { mongoose.disconnect();      mongoose.connect('mongodb://' + uname + ':' + psw + '@localhost:27017/' + dbname);     } 

and index.js

router.post('/choosedb', function (req, res) {       var temp = req.body.country;       if (temp === "india") {         var uname = 'abc';         var psw = 'abc123';         var dbname = 'demodb';         app.getdatabaseconnection(dbname, uname, psw);         res.json('done');       }        else if (temp === "finland") {     var uname = 'xyz';     var psw = 'xyz123';     var dbname = 'testdb';     app.getdatabaseconnection(dbname, uname, psw);     res.json('done');   }      }) 

when first connect india works fine second time when call choosedb api finland gives error like, error: trying open unclosed connection. mongoose.createconnection tried schema like

 var mongoose = require('mongoose');      var schema = mongoose.schema;      var db=require('../app.js');      var garageschema = new schema({ id: string, name: string, address: string });  module.exports = db.model('garage', garageschema);  

which gives me error db.model not function

connect using--

mongoose.createconnection('mongodb://' + uname + ':' + psw + '@localhost:27017/' + dbname) 

and not connect().