Node.js and mongodb TypeError: undefined is not a function

Question

I am new to node.js and mongodb. I am using express and jade for a test app i am writing. I have configured mongodb and node.js but when I try and retrieve data from the database, I get the following error: TypeError: undefined is not a function

/Users/apple/Documents/Nodejs/NODE/express_example/node_modules/mongodb/lib/mongodb/connection/base.js:242
            throw message;      
                  ^
    TypeError: undefined is not a function
        at commandHandler (/Users/apple/Documents/Nodejs/NODE/express_example/node_modules/mongodb/lib/mongodb/cursor.js:706:16)
        at /Users/apple/Documents/Nodejs/NODE/express_example/node_modules/mongodb/lib/mongodb/db.js:1806:9
        at Server.Base._callHandler (/Users/apple/Documents/Nodejs/NODE/express_example/node_modules/mongodb/lib/mongodb/connection/base.js:442:41)
        at /Users/apple/Documents/Nodejs/NODE/express_example/node_modules/mongodb/lib/mongodb/connection/server.js:485:18
        at MongoReply.parseBody (/Users/apple/Documents/Nodejs/NODE/express_example/node_modules/mongodb/lib/mongodb/responses/mongo_reply.js:68:5)
        at null.<anonymous> (/Users/apple/Documents/Nodejs/NODE/express_example/node_modules/mongodb/lib/mongodb/connection/server.js:443:20)
        at EventEmitter.emit (events.js:95:17)
        at null.<anonymous> (/Users/apple/Documents/Nodejs/NODE/express_example/node_modules/mongodb/lib/mongodb/connection/connection_pool.js:191:13)
        at EventEmitter.emit (events.js:98:17)
        at Socket.<anonymous> (/Users/apple/Documents/Nodejs/NODE/express_example/node_modules/mongodb/lib/mongodb/connection/connection.js:418:22)

Here is my code: This is the userlist route that is responsible for fetching the data.

exports.userlist = function(db) {
    return function(req, res) {
        var collection = db.get('usercollection');
        collection.find({},{},function(e,docs){
            res.render('userlist', {
                "userlist" : docs
            });
        });
    };
};

Here is the userlist.jade file:

extends layout

block content
    h1.
        User List
    ul
        each user, i in userlist
            li
                a(href="mailto:#{user.email}")= user.username

Here is the code where I call userlist i.e app.js

/**
 * Module dependencies.
 */

var express = require('express');
var routes = require('./routes');
var user = require('./routes/user');
var http = require('http');
var path = require('path');
var mongo = require('mongodb');
var monk = require('monk');
var db = monk('localhost:27017/nodetest1');

var app = express();

// all environments
app.set('port', process.env.PORT || 3000);
app.set('views', path.join(__dirname, 'views'));
app.set('view engine', 'jade');
app.use(express.favicon());
app.use(express.logger('dev'));
app.use(express.json());
app.use(express.urlencoded());
app.use(express.methodOverride());
app.use(app.router);
app.use(require('stylus').middleware(path.join(__dirname, 'public')));
app.use(express.static(path.join(__dirname, 'public')));

// development only
if ('development' == app.get('env')) {
  app.use(express.errorHandler());
}

app.get('/', routes.index);
app.get('/users', user.list);
app.get('/helloworld', routes.helloworld);
app.get('/userlist', routes.userlist(db));

http.createServer(app).listen(app.get('port'), function(){
  console.log('Express server listening on port ' + app.get('port'));
});

Answer 1

What if you try to modify the find method

exports.userlist = function(db) {
 return function(req, res) {
     var collection = db.get('usercollection');
     collection.find().toArray(function(e,docs){
        res.render('userlist', {
            "userlist" : docs
        });
     });
   };
};