title: How to pass more parameters for socket.on()
body: <p>For socket.on("someChannel", handler), I hope to extract out my handler function to another file. As such, they need to be passed in the socket obj and some more additional info.</p>
  
  <p>Like:</p>
  
  <pre><code>socket.on("myEvt", myEvtHandler);
  
  myEvtHandler(socket, additionalInfo, data) {//some stuff here}
  </code></pre>
  
  <p>But I can't. The best I can think of is to do closure:</p>
  
  <pre><code>(function(socket, addtionalInfo) {
      socket.on("myEvt", function(data) {
          myEvtHandler(socket, addtionalInfo, data);
      });
  })(socket, addtionalInfo);
  </code></pre>
  
  <p>Is this correct? Are there better ways?</p>