TypeError: Cannot read property 'databaseName' of undefined

Question

I've been banging my head against the wall. I've been doing the lynda.com tutorail on essential Node.js and I'm stuck at this point.

When i type nodemon server.js I get the error. I'm having problems exporting the db connection in node.js. Any hints? Is there a better way to debug then make a change and refresh in Node?

/Users/khebert/Sites/node/airline/node_modules/connect-mongo/lib/connect-mongo.js:87
  this.db = new mongo.Db(options.mongoose_connection.db.databaseName,
                                                       ^
TypeError: Cannot read property 'databaseName' of undefined
at new MongoStore (/Users/khebert/Sites/node/airline/node_modules/connect-mongo/lib/connect-mongo.js:87:60)
at module.exports (/Users/khebert/Sites/node/airline/app.js:22:10)
at Object.<anonymous> (/Users/khebert/Sites/node/airline/server.js:4:27)
at Module._compile (module.js:456:26)
at Object.Module._extensions..js (module.js:474:10)
at Module.load (module.js:356:32)
at Function.Module._load (module.js:312:12)
at Function.Module.runMain (module.js:497:10)
at startup (node.js:119:16)
at node.js:901:3
2 Jan 08:04:56 - [nodemon] app crashed - waiting for file changes before starting...

db.js

var mongoose = require('mongoose');
mongoose.connect('mongodb://localhost/flights', function(err) {
    if (err) console.log(err);
    else console.log('DB success');
});

module.exports = mongoose.connections;

server.js

var http = require('http'),
    flights = require('./data'),
    db = require('./db'),
    app = require('./app.js')(flights, db);
http.createServer(app).listen(app.get('port'), function(){
  console.log('Express server listening on port ' + app.get('port'));
});

app.js

module.exports = function(flights, db) {

/**
 * Module dependencies.
 */

var express = require('express');
var MongoStore = require('connect-mongo')(express);
var routes = require('./routes')(flights);
var path = require('path');
var app = express();

// all environments
app.set('port', process.env.PORT || 3000);
app.set('views', __dirname + '/views');
app.set('view engine', 'jade');
app.use(express.favicon());
app.use(express.logger('dev'));
app.use(express.cookieParser());
app.use(express.session({ 
        secret: 'keyboard cat', 
        store: new MongoStore({ 
            mongoose_connection: db
    })
}));
app.use(express.bodyParser());
app.use(express.methodOverride());
app.use(function (req, res, next) {
    res.set('X-Powerd-By','Flight Tracker');
    next();
});
app.use(app.router);
app.use(express.static(path.join(__dirname, 'public')));

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

app.get('/flight/:number', routes.flight);
app.put('/flight/:number/arrived', routes.arrived);
app.get('/list', routes.list);
app.get('/arrivals', routes.arrivals);

    return app;
};

Answer 1

In db.js,

module.exports = mongoose.connections;

change to:

module.exports = mongoose.connections[0];

Answer 2

It might be a problem with the 'express.bodyParser()', you have to define your connections AFTER all the configuration of your app.

Answer 3

You can just reuse the db object already instantiated by mongoose!

new MongoStore({
  db: mongoose.connection.db
})