slotRenderEnded listener event (DFP)

gistfile1.js

googletag.pubads().addEventListener("slotRenderEnded", function(event) {

  //console.log("googletag slotRenderEnded", event.slot.b.f);
  var containerId = "";

  // WARN: Fragile access of private object within DFP Slot Object returned with the event
  //       It's the only way to get access to the id of the DOM element attached to the slot
  // FIXME: Ideally we need to contact Google and request a public API method to return the id
  if (typeof event.slot !== "undefined") {
    if (typeof event.slot.b !== "undefined") {
      if (typeof event.slot.b.f !== "undefined") {
        containerId = "#" + event.slot.b.f;
      }
    }
  }


  if (containerId !== "") {
    if (event.isEmpty === false) {
      // not an entirely safe access of private areas in the GPT Slot object
      // [Obj].b.d is a volatile reference
      //containerId = "#" + event.slot.b.d;
      $(containerId).closest('.media')
        .addClass('has-ad ' + $(containerId).data('adunit'))
        .trigger("sponsorship:has-ad");
    }
    // Fired whether or not the slot has an ad,
    // once render loop is completed
    $(containerId).trigger("sponsorship:rendered");
  } else {
    //console.warn("Sponsorship: Failure to detect ad unit ID from Google Slot object");
  }


});

If I understand this correctly, why not just use the pubads slot api?

event.slot.getSlotElementId();

Line 9-15 could be something like:

var containerId = ( ( event.slot || {} ).b || {} ).f;

if(!!containerId) {
    containerId = `#${containerId}`;
    ...