docs: function (event) {
          // https://github.com/angular/zone.js/issues/911, in IE, sometimes
          // event will be undefined, so we need to use window.event
          event = event || _global.event;
          if (!event) {
              return;
          }
          // event.target is needed for Samsung TV and SourceBuffer
          // || global is needed https://github.com/angular/zone.js/issues/190
          var target = this || event.target || _global;
          var tasks = target[zoneSymbolEventNames$1[event.type][FALSE_STR]];
          if (tasks) {
              // invoke all tasks which attached to current target with given event.type and capture = false
              // for performance concern, if task.length === 1, just invoke
              if (tasks.length === 1) {
                  invokeTask(tasks[0], target, event);
              }
              else {
                  // https://github.com/angular/zone.js/issues/836
                  // copy the tasks array before invoke, to avoid
                  // the callback will remove itself or other listener
                  var copyTasks = tasks.slice();
                  for (var i = 0; i < copyTasks.length; i++) {
                      if (event && event[IMMEDIATE_PROPAGATION_SYMBOL] === true) {
                          break;
                      }
                      invokeTask(copyTasks[i], target, event);
                  }
              }
          }
      }