CODEWITHSUNDEEP
angularjsangularjs-templates
DanEEStar
DanEEStar

Reputation: 6280

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

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

Upvotes: 22

Views: 64809

Answers (5)

Chris Halcrow
Chris Halcrow

Reputation: 31950

You can convert the object to a JSON string using the built-in AngularJS json filter and do a comparison like this:

<div ng-if="vm.testObject | json) != '{}'">
    Test Object is not empty
</div>

Upvotes: 0

L105
L105

Reputation: 5419

This is an old thread but I find easier to check if the Object has keys.

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

It's simple and readable.

Upvotes: 1

Mohammad Fareed
Mohammad Fareed

Reputation: 1972

This will work. check the Length

<div ng-if="!!vm.testObject && vm.testObject.length > 0">
  Test Object is not empty
</div>

Upvotes: 0

Numyx
Numyx

Reputation: 1758

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

Upvotes: 43

thekaveman
thekaveman

Reputation: 4399

Are you ok with moving the equality check to the ng-if?

<div ng-controller="TestController as vm">
  <div ng-if="!equals({}, vm.testObject)">
    Test Object is not empty
  </div>
  <div ng-if="equals({}, vm.testObject)">
    Test Object is empty
  </div>
</div>

Otherwise, provide a helper on the scope

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

  vm.testObject = {};

  vm.empty = function() {
      return vm.testObject === {};
  };
});

then

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

Upvotes: 24

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