an AngularJs controller that uses a promise to subscribe to call a remote service and handle the results

controller-promise.js

var myApp = angular.module('myApp',[]);
  
myApp.controller('FooController', ['$scope', 'fooService', function($scope, fooService) {
    var instance = this;
    
    $scope.loadingStatus = 'none';
    
    instance.onBarCompleted = function(){
      $scope.loadingStatus = 'completed';
    };
    instance.onBarError = function(){
      $scope.loadingStatus = 'error';
    };
    
    $scope.callBar = function() {
      $scope.loadingStatus = 'loading...';
      
      fooService.bar()
                .then(instance.onBarCompleted)
                .catch(instance.onBarError);
    }
}]);