orszaczky orszaczky - 2 months ago 22
AngularJS Question

ng-class condition changes, but not updating classes

I have a very strange issue. I have to set an

active
class on the appropriate
<li>
when the
$scope.selectedCat == cat.id
. The list is generated with ng-repeat. If selectedCat is false, the 'Browse All Categories' list item (outside of ng-repeat) is set to active.
setCat()
sets the value of the
$scope.selectedCat
variable:

<div id="cat-list" ng-controller="CatController">
<li ng-class="{'active': {{selectedCat == false}}}">
<a>
<div class="name" ng-click="setCat(false)" >Browse All Categories</div>
</a>
</li>
<li class="has-subcat" ng-repeat="cat in cats | filter:catsearch" ng-class="{'active': {{selectedCat == cat.id}}}">
<a>
<div cat class="name" ng-click="setCat({{cat.id}})" ng-bind-html="cat.name | highlight:catsearch"></div>
</a>
</li>
</div>


When the page loads, everything works fine (snapshot from FireBug):

<li ng-class="{'active': true}" class="ng-scope active">
<!-- ngRepeat: cat in cats | filter:catsearch -->
<li class="has-subcat ng-isolate-scope" ng-repeat="cat in cats | filter:catsearch" ng-class="{'active': false}">


However when I set $scope.selectedClass to a
cat.id
value, the condition within ng-class gets evaluated correctly, but ng-class won't update the classes accordingly:

<li ng-class="{'active': false}" class="ng-scope active"> <!--Right here!-->
<!-- ngRepeat: cat in cats | filter:catsearch -->
<li class="has-subcat ng-isolate-scope" ng-repeat="cat in cats | filter:catsearch" ng-class="{'active': true}">


Please note that in the first line active class stays set, while ng-class evaluates to false. In the last line active is not set, while ng-class evaluates to true.

Any ideas why it doesn't work? What's the correct Angular way of doing this?

Answer

Replace:

ng-class="{'active': {{selectedCat == cat.id}}}"

With:

ng-class="{'active': selectedCat == cat.id}"

You never need to nest those curly braces like that, in Angular.

Have a look at the ng-class documentation for some more examples.