title: node.js - post response is not waiting for callback to complete
body: <p>I am working on node.js http server. The Server is connected to mongodb. I am requesting a post request to the server to get documents from mongodb. But the post response is not waiting for mongodb callback to complete. And therefore I am not getting required output on the client side. How to handle this?</p>
  
  <pre><code>http.createServer(function(request, response) {
      if(request.method == "POST") { 
          var body = '';
          request.on('data', function(chunk) {
              console.log(chunk.toString());
              body += chunk;
          });
          request.on('end', function() {
              MongoClient.connect("mongodb://localhost:27017/exampleDb", function(err, db) {
                  if(err) {
                      console.log("We are not connected");
                  }   
                  else {
                      var sysInfo = db.collection('sysInfo');
                      var jsonObj = sysInfo.find().toArray();
                      response.writeHead(200, {'Content-Type': 'text/plain'});
                      response.end(jsonObj);
                  }
              });
          })
      }
  });
  </code></pre>