no support for handleEvent

[WebReflection]

The EventTarget interface, which is also already polyfilled in here, supports handleEvent method through objects/instances.

callback interface EventListener {
  void handleEvent(Event event);
};

This polyfill breaks standard behavior when an object, instead of a callback, is passed as listener and the third parameter is an object too.

More on the topic, with various use cases and explained benefits, in this post.

[WebReflection]

is this a death/abandoned project?

[WebReflection]

I assume it is.