I'm relatively new to Express and Node but this seems like a VERY basic demand and I am struggling to understand how it could be happening. Any help in solving the problem or identifying how I'd troubleshoot it would be VERY appreciated.

Problem

var 
    express = require('express'),
    bodyParser = require('body-parser'),
    logger = require('morgan'),
    express = require('express'),
    app = express();

app.get('/heartbeat', function(req,res) {
    res.status(200).json(req.header('host'));
});

// my simple middleware component
app.use(function (req, res, next) {
    console.log('made it');
    next();
});
// standard middleware components
app.use(logger('dev'));
app.use(bodyParser.urlencoded({ extended: true })); 

// Start listener
app.listen(4400);

This simple program does output my "made it" console message but yet when I wrap all the code (minus the variable definitions) in a function called start:

var 
    express = require('express'),
    bodyParser = require('body-parser'),
    logger = require('morgan'),
    express = require('express'),
    app = express();

var start = function(config) { ... }
exports.start = start;

and then call start from a separate module I find that the logging and bodyParser modules seem to execute but my middleware component is ignored. I'm pulling my hair out trying to figure why.