Should work with objects that have their own event system

[matthewp]

can-define should work with objects that already have an addEventListener, such as dom elements.

[matthewp]

I'll create a test with an object that has its own mini event emitter system so we can better look at the solution.

[matthewp]

Added a test here: c93641f

[matthewp]

@justinbmeyer I did a quick and dirty implementation that uses the element's native addEventListener here: 4fbb7eb

The result of that change is that the DOM events now fire but the property events do not (without that change the opposite happens).

[matthewp]

Last I left off with this there was a problem with can-observation expecting 3 argument events.

I patched my local can-observation to fix this:

onDependencyChange: function(ev, newVal, oldVal){
  if(arguments.length === 1 && Array.isArray(ev.args)) {
    newVal = ev.args[0];
    newVal = ev.args[1];
  }

  this.dependencyChange(ev, newVal, oldVal);
},

However, it still fails because there is no batchNum associated with this event:

The problem is that I changed can-define to use canEvent.trigger, which triggers real DOM events if it's a DOM element. However this fails because there is no batch stuff happening now.

So I'm not sure how to fix this now. I suppose maybe canEvent.trigger might need to do some batching.

[justinbmeyer]

@matthewp I've been thinking about this probably and how it relates to can-operate.onKeyValue. Some event systems won't have a batchNum. It might be possible to "force" this via the onKeyValue symbol / setup. Can explain more later.

[justinbmeyer]

@matthewp can-operate only expects a onKeyValue that will be called with the new value. We should talk about what this will mean for this effort.