如何在angularjs的for循环中动态创建$ rootScope。$ on事件侦听器

Question

I want to dynamically create event listeners in an angularjs service, however it seems that each $rootScope.$on event listener I create in the for loop in the service is overwritten by the following event listener. How can I dynamically create $rootScope.$on even listeners without overwriting the previous event listener? I create events using broadcasts from my controller like $rootScope.$broadcast(EVENTS.userDeleteSuccess.event); .

My EVENTS constant looks like:

myApp.constant('EVENTS', {
    userDeleteSuccess: {
        event: 'user-delete-success',
        type: 'success',
        message: 'User successfully deleted'
    },
    ...,
    siteDeleteSuccess: {
        event: 'site-delete-success',
        type: 'success',
        message: 'Site successfully deleted'
    }
}

My service looks like:

myApp.service("Alert", function($rootScope, EVENTS) {

    var show = function(type, message) {

        $rootScope.alert = {
            type: type,
            message: message,
            show: true
        };
    };

    // Initialized on application startup, this is the problem method!

    this.initialize = function() {
        for(var event in EVENTS) {
          if(!EVENTS.hasOwnProperty(event)) break;
          var _event = EVENTS[event];
          $rootScope.$on(_event.event, function() {
            show(_event.type, _event.message);
          });
        }
      };

      return this;
});

The only event that ever gets broadcasted is always the last event in the object ( siteDeleteSuccess in this case). How can I dynamically create an event listener in a for loop that doesn't overwrite the previous $rootScope.$on event listener?

Answer 1

You can do two things use an IIFE or just bind the argument(s) so they get passed into the function

IIFE

(function(event){
    $rootScope.$on(event.event, function() {
        show(event.type, event.message);
    });
})(_event);

Binding:

$rootScope.$on(_event, function(event) {
    show(event.type, event.message);
}.bind(null,_event));

bind docs