Im using ui-validate utils https://github.com/angular-ui/ui-validate
The problem is to validate expression on the form without input field. For example? I have an object
$scope.item = { field1 : 0, field2: 0, field3: 0 };
I would like to receive the error, provided expression: field1 + field2 + field3 == 0
It is common validation for the whole form. Not for some input.