Fire event with this.emit(...)?

Hi Everyone! On Puck I try to organize communication between objects with events (see Object.emit and discussion here). However, I cannot emit an event within a prototype function with 'this'. Thus if e.g. I have two step up modules, I cannot subscribe directly to each of them, and need to add either a module id as an event argument or additional empty object (see below).

In comments here is what I'd want:

function aClass() {};

aClass.prototype.testEmit = function() {
  setTimeout(()=>aClass.emit('TestEvent'),­ 1000); //this.emit(...) here will not emit!
}

var a = new aClass();
aClass.on('TestEvent', ()=>console.log('Got event')); //would like 'a.on(...)'
a.testEmit();  // get 'Got event' printed in log

var a1 = new aClass();
a1.testEmit(); // get another 'Got event' printed in log

Here is a way round with an empty object:

function aClass() {
  this.emitter = {};
};

aClass.prototype.testEmit = function() {
  setTimeout(()=>this.emitter.emit('TestEv­ent'), 1000); //now it works
}

var a = new aClass();
a.emitter.on('TestEvent', ()=>console.log('Got event')); //now we subscribe only to a
a.testEmit(); //get 'Got event' in console

var a1 = new aClass();
a1.testEmit(); //get nothing

Why can't I use this.emit(...)?