AngularJS - ng-class

<!DOCTYPE html>
<html>

  <head>
    <link rel="stylesheet" href="style.css">
    <script src="//code.jquery.com/jquery-2.2.4.js"></script>
    <script src="//code.angularjs.org/1.6.0/angular.min.js"></script>
    <script src="script.js"></script>
  </head>

  <body ng-app="app" ng-controller="ctrl">
    <div ng-class="{true: 'class1', false: 'class2'}[(ctrl.parameter || !last)]">This is a test</div>
    
  </body>

</html>

angular.module("app", []).controller("ctrl", function($scope){

$scope.ctrl = {
  parameter: false
}

$scope.last = true;
});

.class1 {
  border: 1px solid blue;
}
.class2 {
  border: 1px solid red;
}