Need a way to access target for eventTasks

[hmdhk]

In newest versions of zone.js task.data.target is removed, is there anyway to access target for eventTasks?

[JiaLiPassion]

@jahtalab , you can call target.eventListeners(eventName) to get all listeners by eventName.

[hmdhk]

@JiaLiPassion, Thanks! I specifically need this for XMLHttpRequest, I have the target when the send method is called but eventTasks like readystatechange and load doesn't have target and I need to keep track of the events that are registered for XHR.

Calling target.eventListeners(eventName) when send is being scheduled only gives me the callbacks but I need to keep track of eventTasks and get notified when they're called.

Another problem is that for XHR it's possible to register those events after you call send (not a good practice but still possible) and then calling target.eventListeners(eventName) wouldn't even include those events.

Is there a problem with adding target to task data here: https://github.com/angular/zone.js/blob/master/lib/common/events.ts#L398

[JiaLiPassion]

@jahtalab , could you post some sample code to describe what you need?

[hmdhk]

@JiaLiPassion ,

Here's some code (it's not exactly the code that I'm using but a simplified version):
Let me know if I need to clarify anything.

Zone.current.fork({
  onScheduleTask: function (parentZoneDelegate, currentZone, targetZone, task) {
    var test = task.data.target['__test_symbol__'] || (task.data.target['__test_symbol__'] = {})
    test[task.source] = false
    if (task.source === 'XMLHttpRequest.send') {
      test.startTime = performance.now()
    }
    return parentZoneDelegate.scheduleTask(targetZone, task)
  },
  onInvokeTask: function (parentZoneDelegate, currentZone, targetZone, task, applyThis, applyArgs) {
    var test = task.data.target['__test_symbol__']
    test[task.source] = true

    var result = parentZoneDelegate.invokeTask(targetZone, task, applyThis, applyArgs)
    if (test['XMLHttpRequest.send'] && test['XMLHttpRequest.addEventListener:readystatechange'] && test['XMLHttpRequest.addEventListener:load']) {
      test.endTime = performance.now()
      console.log('XHR timing:', test.endTime - test.startTime)
    }
    return result
  }
}).run(function () {
  function reqListener () {
    console.log('XMLHttpRequest.load')
  }

  var oReq = new window.XMLHttpRequest()
  oReq.addEventListener('readystatechange', function () {})
  oReq.addEventListener('load', reqListener)

  oReq.open('GET', '/', true)
  oReq.send(null)
})

target is the object that binds eventTasks and the macroTask, That's why it's need on the eventTasks.

[JiaLiPassion]

@jahtalab , so you want to get target from task? you can try task.target.

[hmdhk]

@JiaLiPassion , I need the target in onScheduleTask callback. here task.target is set after the zone.scheduleEventTask call. Which makes sense since the onScheduleTask is supposed to return the new task. But it also means I can't access target in onScheduleTask.

[JiaLiPassion]

@jahtalab , I see, I will create a patch to let onScheduleTask access target, because task will keep a reference to data, so I also need to clean up the target from data after scheduleEventTask.