A sample HTTP server application for tutorial here: http://mostafa-samir.github.io/async-recursive-patterns-pt2/

server.js

var http = require('http');

var server = http.createServer(function(request, response) {
   
   var randomNetworkDelayFactor = Math.floor(Math.random() * 99) + 1;
   
   // simulates a random network delay up to one second
   setTimeout(function() {
      var request_path = request.url;
    
      response.writeHead(200, {"Content-Type": "application/json"});
    
      if(request_path === '/meta/moduleA') {
           
         var dataA = JSON.stringify({
            "hasDependency": true,
            "dependency": "moduleB"
         });
        
         response.end(dataA);        
      }
      else if(request_path === '/meta/moduleB') {
           
         var dataB = JSON.stringify({
            "hasDependency": true,
            "dependency": "moduleC"
         });
        
         response.end(dataB);
      }
       else if(request_path === '/meta/moduleC') {
           
         var dataC = JSON.stringify({
            "hasDependency": false,
         });
        
         response.end(dataC);
      }
      else {
         response.end(JSON.stringify({
			"err": "NOT FOUND"
		 }));
      } 
   }, randomNetworkDelayFactor * 10);
});

server.listen(8080);
console.log("The server is running on http://localhost:8080");