app.js

'use strict';

var http = require('http');
var express = require('express');
var enrouten = require('enrouten');


var app, server;

app = express();

/**
 * Index Mode
 * Dependencies are provided, in order, to all scanned files within
 * a directory, in addition to the existing `router` argument.
 */
app.use(enrouten({
     "mode": {
        "type": "index",
        "options": "./controllers",
        "dependencies": ["config", "misc"]
    },
    "providers": {
        "config": {},
        "misc": {}
    }
}));

/**
 * Directory Mode
 * Dependencies are provided, in order, to configured index file in
 * in addition to the existing `router` argument.
 */
app.use(enrouten({
    "mode": {
        "type": "directory",
        "options": "./routes",
        "dependencies": ["config"]
    },
    "providers": {
        "config": {}
    }
}));

/**
 * Routes Mode
 * Top-level dependencies are injected to *all* routes that omit a dependency
 * declaration of their own. If a route definition declares dependencies, that list
 * supercedes the global list.
 */
 /*
 UPDATE: This can't/does not need to change.
app.use(enrouten({
     "mode": {
        "type": "routes",
        "options": [
            { path: '/',    method: 'GET', handler: require('./routes/index') },
            { path: '/foo', method: 'GET', handler: require('./routes/foo'), dependencies: ["misc"] } // Overrides parent deps
        ],
        "dependencies": ["config", "misc"] // Apply to all routes unless overridden
    },
    "providers": {
        "config": {},
        "misc": {}
    }
}));
*/

module.exports = app;

controllers_index.js

'use strict';

var db = require('./mydb');

module.exports = function (router, config) {
     var conn = db.createConnection(config.db);
     
     router.get('/db', function (req, res) {
          // do stuff with db
          res.end('ok');
     });
};

routes.js

'use strict';

module.exports = function (router, config, misc) {
     
     if (config.env.dev) {
          router.get('/test', function (req, res) {
               res.end('test');
          });
     }
     
};

routes_foo.js

'use strict';

var db = require('./mydb');

module.exports = function (router, misc) {
     
     router.get('/', function (req, res) {
          res.end('ok');
     });
     
};

routes_index.js

'use strict';

var db = require('./mydb');

module.exports = function (router, config, misc) {
     
     router.get('/', function (req, res) {
          res.end('ok');
     });
     
};

"providers" is such non-obvious DI jargon. It's a lot of concept to import.

"dependencies", too, is non-obvious. To document this, we'd have to explain essentially all of DI. And why our flavor of DI.)