Cannot read property 'insert' of undefined - node.js

Question

This is my first Node.js program using the Mongo db. This is my code:
/**
* Module dependencies.
*/
var express = require('express')
, routes = require('./routes')
, user = require('./routes/user')
, http = require('http')
, path = require('path');
var mongo = require("./routes/mongo");
var session = require('express-session');
var MongoClient = require('mongodb').MongoClient;
var assert = require('assert');
var monStore=require("connect-mongo")(session);
var url = 'mongodb://localhost:27017/session';
var app = express();
app.configure(function(){
app.set('port', process.env.PORT || 4000);
app.set('views', __dirname + '/views');
app.set('view engine', 'ejs');
app.use(express.favicon());
app.use(express.logger('dev'));
app.use(express.bodyParser());
app.use(express.methodOverride());
app.use(app.router);
app.use(express.static(path.join(__dirname, 'public')));
});
app.configure('development', function(){
app.use(express.errorHandler());
});
app.get('/', routes.index);
app.get('/users', user.list);
app.post('/signup',function(req,res){
var email=req.param("email");
var fname=req.param("firstname");
var lname=req.param("lastname");
var password=req.param("password");
var url1="mongodb://localhost:27017/signup";
mongo.connect(url1, function(){
var db= mongo.collection('user');
db.user.insert({"username": email,
"password":password,
"firstname":fname,
"lastname":lname});
res.render("login",{title:"welcome"});
});
});
app.post('/login',function(req,res){
var email=req.param("email");
var password=req.param("password");
var url1="mongodb://localhost:27017/login";;
mongo.connect(url1, function(){
var db= mongo.collection('signup');
db.findOne({username: email, password:password}, function(err,user){
console.log(user.email);
if(user)
{
res.render("welcome");
}
else
{
res.render("login",{title:"ivalid"});
}
});
});
});
MongoClient.connect(url, function() {
console.log("Connected correctly to server.");
});
http.createServer(app).listen(app.get('port'), function(){
console.log("Express server listening on port " + app.get('port'));
});
i get the error Cannot read property 'insert' of undefined where i am trying to insert values into the database. Am I missing some point here? Can somebody Please help me out?

Answer 1

You are using db variable as a reference to the collection:
var db= mongo.collection('user');
db.user.insert({"username": email,
...
The collection has no attribute called user, so that calling insert on it results in your error.
I believe that you wanted to do this:
var userCollection = var db= mongo.collection('user');
userCollection.insert({"username": email,
...