(just a test, this is written by @rtablada not me)
After working with a lot of node modules I'm a bit angered by the fact that for a lot of these packages you have to pass around and keep track of a single shared instance throughout your application.
This works fine for small proxy servers and apps where the whole thing fits into a single
app.js or maybe a handful of route files.
But as things start to grow this model really breaks down and becomes cumbersome.
Just think about a resource file for
app/resources/users.js which needs the current Redis or RabbitMQ connection to publish events like user registration, a database connection to persist things, and probably a Socket.io instance because it's Real Time: it's so hot right now!
If you export a function that allows these to be injected, your resource has boilerplate.