How to use the ChromeApp to connect to a node.js server?

I have a Node.js server and I'd like to know how I could do for the ChromeApp to work with it. I tried putting "http://localhost:3000" (server address) on the runtime:

chrome.app.runtime.onLaunched.addListener(function () {
   chrome.app.window.create('http://localhost:3000');
});

But it doesn't even launch. Does someone have an idea on what I could do? Thanks.