Is there a way to get back anonymous event handlers that were registed with Event.observe in Prototype?

Question

Interfacing with legacy code, and I've got something like this:

Event.observe(some_form, 'submit', [some anonymous function])

I'd like to grab that anonymous event handler back out, is there an easy way to do that in Prototype?

Answer 1

If you actually want access to the handler, no, there's no easy way. You can of course stopObserving all prototype initiated handlers for an event type, but I don't think that's what you're looking for.

Answer 2

If there aren't too many other listeners on some_form + submit-event or you control all others you could get at it with

var boundSubmitEvents = some_form.getStorage().get('prototype_event_registry').get('submit');
boundSubmitEvents.each(function(wrapper){
    //do with wrapper.handler whatever
})

btw. what do you mean with

grab that anonymous event handler back out

Answer 3

It depends on the version of Prototype. From a more general answer I wrote previously:

• version 1.5.x:

  // inspect
  Event.observers.each(function(item) {
      if(item[0] == some_form && item[1] == 'submit') {
          alert(item[2]) // [some anonymous function]
      }
  })
  

• versions 1.6 to 1.6.0.3, inclusive (got very difficult here)

  // inspect. "_eventId" is for < 1.6.0.3 while 
  // "_prototypeEventID" was introduced in 1.6.0.3
  var submitEvents = Event.cache[some_form._eventId || (some_form._prototypeEventID || [])[0]].submit;
  submitEvents.each(function(wrapper){
      alert(wrapper.handler) // [some anonymous function]
  })
  

• [Current] version 1.6.1 (little better)

  // inspect
  var submitEvents = some_form.getStorage().get('prototype_event_registry').get('submit');
  submitEvents.each(function(wrapper){
      alert(wrapper.handler) // [some anonymous function]
  })