Serial.on() issues...

How do I make this work here?

function EasyVR(ser,onCm,onTo) {
  this.ser = ser;
  this.onCommand=onCm;
  this.onTimeout=onTo;
  this.ser.on('data',this.onWatch);
  this.vrstate=-1;
  this.stsr='o';
  this.rcvv="";
} ;

EasyVR.prototype.onWatch=function(data) {
	console.log(this);
};

This seems to be set to... an object containing everything. How do I get it to be the object that the function is a property of?

Secondly - with same code, try doing:

evr.onWatch=function(){console.log("roar­!!!");} //where evr is an instance of that object

then provoke another serial data event. The callback isn't updated. How can I make it call the function I pointed it at, instead of remembering what said function happened to be when I initially set up the callback? Is this behavior intended?

Thanks