Basic NodeJS dependency injection pattern example.

index.js

var server = require("./server");
var router = require("./router");
server.start(router.route); //Injecting router as parameter.

router.js

function route(pathname) {
  console.log("Route a request for: " + pathname);
}
exports.route = route;

server.js

var http = require("http");
var url = require("url");

function start(route) {
  function onRequest(request, response) {
    var pathname = url.parse(request.url).pathname;
    console.log("Request from: " + pathname );
    route(pathname);
    response.writeHead(200, {"Content-Type": "text/plain"});
    response.write("Response write");
    response.end();
  }
  http.createServer(onRequest).listen(8888);
}
exports.start = start;