Can I resolve a promise from a broadcasted event?

Question

We're using angular legacy (1.5) I am trying to bulk load some layers using a 3rd party library. I need to wait till they are loaded before continuing. So in my get data section, it calls the library and asks it to add data, I start a $q.defer in this section and assign this to a factory level variable. In the service for the 3rd party lib, I setup a count for requests out and requests in, when they match, the $broadcast and event to tell me its complete. I then listen ($on) for this event and set the promise to resolved. however the application doesn't wait for this. I understand this is a strange one, but what can I do.

Our code is quite involved, so I have tried to create crude example of what we are trying to archive.

function layerFactory($rootScope, $log, $q, DataService) {
    var factory = {
        getData:getData,              
        var _dataPromise;
        function getData(data){
             _getLayerData(data).then(function(){
                 _processData(data);
             });                 
        }  
        function _getLayerData(data){
             _dataPromise = $q.defer();
             DataService.getData(data) // Treat DataService as a 3rd party lib, this doesn't return a promise.  I have no way of knowing this is complete until a $broadcast is sent.
             _dataPromise.promise;
        }

        $rootScope.$on('dataLoaded', function(){
            _dataPromise = $q.resolve();
        });
}
    return factory;
}

This isn't waiting for the promise to resolve and instead going into the 'then' statement and processing the next function 'too early' I need it to wait till the first function as finished.

Any ideas?

Answer 1

Ok, I couldn't find a way to make this work, so what I did instead was to set a factory level variable (boolean) to indicate when the loading had started, this was then set to false when the $on event was triggered. In my getLayerData method, I set up an internal to run every 500 ms, inside this interval function I run a check for the loading variable, if false (ie loaded), then return a deferred.resolve() and cancel the interval.