EventListenerList should be parameterized by the event type

[justinfagnani]

Currently classes that use Events subclasses and EventListenerList don't offer enough assistance in the Dart editor.

For example, Element.on.click takes a function that takes a MouseEvent, but that's not specified in the ElementEvents interface.

The interfaces could be defined like this:

interface EventListenerList<E> { // In Java I'd write <E extends Event>, unsure what to do in Dart
  add(void handler(E event), [bool useCapture];
  ...
}

interface ElementEvents extends Events {
  ...
  EventListenerList<MouseEvent> get on();
  ...
}

Then the editor could check that the handler was of the correct type.

[justinfagnani]

Oops, I totally messed up on the ElementEvents interface. on() should be click().

[sethladd]

Removed Type-Defect label.
Added Type-Enhancement, Area-DOM, Triaged labels.

[iposva-google]

Removed Area-DOM label.
Added Area-HTML label.

[rakudrama]

We don't have a source of information for doing this automatically - the correspondence is not in the IDL.
We could do it manually.
I'm not sure that the types are 100% reliable - you could dispatchEvent an event of the wrong type and in JavaScript, at least, it would probably work just fine.

We will revisit after M1

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Added this to the Later milestone.

[blois]

Removed this from the Later milestone.
Added this to the M2 milestone.

[blois]

Added events label.

[blois]

Set owner to @blois.
Added Accepted label.

[blois]

Removed this from the M2 milestone.
Added this to the M3 milestone.

[blois]

New DOM event streams are now parameterized.

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Added Fixed label.