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

How about a function, eg `vm.isEmpty = function(obj) { return Object.keys(obj).length === 0; }`. Then you can use `ng-if="vm.isEmpty(vm.testObject)"` — Phil, May 21 '15 at 07:17

Numyx · Answer 1 · 2015-05-21T07:29:35.007

43

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

edited May 21 '15 at 07:29

answered May 21 '15 at 07:22

Numyx

1,758
2
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16

1

You're right, thanks for helping me out there! Just corrected the answer. – Numyx May 21 '15 at 07:30
3

For isNotEmpty `return !angular.equals({}, object);` – Kevin Campion Jan 10 '17 at 23:34
like this solution based on angular's framework instruments, i guess it is in a "canonical way" to archieve this goal – Victor Sep 19 '19 at 14:25

score 24 · Accepted Answer · answered May 21 '15 at 07:21

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>

Does this helper even work? In Javascript `{} === {}` gives false. — Lukasz Wiktor, Mar 16 '16 at 08:30
vm.empty = function(object) { return Object.keys(object).length === 0; }; — A. Matías Quezada, Sep 07 '16 at 19:45

score 1 · Answer 3 · answered Dec 10 '18 at 14:27

1

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.

answered Dec 10 '18 at 14:27

L105

5,379
3
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23

Actually, this didn't work for me. Upvoted by mistake. – Akin Williams Jul 23 '19 at 14:19
it doens't works for me. Using version 1.3.1 (yeah, i know that is older..) – Victor Sep 19 '19 at 14:23

score 0 · Answer 4 · answered Jun 15 '17 at 12:00

0

This will work. check the Length

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

answered Jun 15 '17 at 12:00

Mohammad Fareed

1,927
6
26
59

score 0 · Answer 5 · answered Oct 07 '21 at 22:13

0

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>

answered Oct 07 '21 at 22:13

Chris Halcrow

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18
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Test if an object is an empty object in a AngularJS template

5 Answers5