Test if an object is an empty object in a AngularJS template

Question

I have a simple object in a controller which can sometimes be empty ({}).

app.controller('TestController', function() {
  var vm = this;

  vm.testObject = {};
});

I want to hide or show some DOM-elements in the corresponding template when the object is empty or not.

I tried to do it with a simple <div ng-if="vm.testObject"> but when vm.testObject === {} it is considered true in the ng-if.

<div ng-controller="TestController as vm">
  <div ng-if="vm.testObject">
    Test Object is not empty
  </div>
  <div ng-if="!vm.testObject">
    Test Object is empty
  </div>
</div>

Is there a simple way to check for an empty object in the template? Preferably without adding new variables to the scope.

Here is a working Plunker: http://plnkr.co/edit/Qed2MKmuedcktGGqUNi0?p=preview

Answer 1

You should use an AngularJs filter:

Javascript:

app.filter('isEmpty', [function() {
  return function(object) {
    return angular.equals({}, object);
  }
}])

Html template:

<div ng-if="!(vm.testObject | isEmpty)">
  Test Object is not empty
</div>
<div ng-if="vm.testObject | isEmpty">
  Test Object is empty
</div>

Updated plunkr: http://plnkr.co/edit/J6H8VzUKnsNv1vSsRLfB?p=preview