Dynamically changing classes using ng-class



The order of the class names changes on ng-class condition.
On initiation the class remains as expected
<div ng-class="{ 'six wide column' : role === USER, 'five wide column' : vm.role === coach }">

but on change of role the class name changes to “wide six column”, and semantic css is not applied because change in class order.

Thank for help in advance.