new implement: Implemented an event call after and before Csv file ex…

…port, issue ID: #166

src/ng-csv/directives/ng-csv.js

@@ -5,7 +5,7 @@
  * Author: asafdav - https://github.com/asafdav
  */
 angular.module('ngCsv.directives').
-  directive('ngCsv', ['$parse', '$q', 'CSV', '$document', '$timeout', function ($parse, $q, CSV, $document, $timeout) {
+  directive('ngCsv', ['$parse', '$q', 'CSV', '$document', '$timeout', 'CSVBroadcast', function ($parse, $q, CSV, $document, $timeout, CSVBroadcast) {
     return {
       restrict: 'AC',
       scope: {
@@ -108,11 +108,13 @@ angular.module('ngCsv.directives').
         }
 
         element.bind('click', function (e) {
+		  CSVBroadcast.broadcastEvent("CSV.beforeDownload");
           scope.buildCSV().then(function (csv) {
             doClick();
+			CSVBroadcast.broadcastEvent("CSV.downloaded");
           });
           scope.$apply();
         });
       }
     };
-  }]);
+  }]);

src/ng-csv/services/csv-service.js

@@ -167,3 +167,25 @@ angular.module('ngCsv.services').
 
 
   }]);
+
+  angular.module('ngCsv.services').
+  service('CSVBroadcast', function ($rootScope) {
+	/**
+     * Helper function to calling an event after export
+     * Function calls $rootScope.$broadcast(@eventName)
+     * @param eventName
+     */
+	this.broadcastEvent = function(eventName){
+		$rootScope.$broadcast(eventName); 
+	}
+
+	/**
+     * Helper function to calling an event after export
+     * Function invoked when event fired on $rootScope.$broadcast(@intput)
+	 * callback function executed on event
+     * @param eventName
+     */
+	this.listenEvent = function(eventName, callback) {
+		$rootScope.$on(eventName,callback);
+	}
+});