The solution is using $parsers and $formatter.
Try this directive:
app.directive("csRadioFieldFormat", function() {
return {
require: 'ngModel',
restrict: 'A',
link: function(scope, element, attrs, ctr) {
ctr.$parsers.unshift(function(value) {
var isValid = value !== "";
ctr.$setValidity("required", isValid);
if (!isValid){
return undefined;
}
if (value.indexOf(attrs.suffix) < 0) {
value = value + attrs.suffix;
}
return value;
});
ctr.$formatters.unshift(function(value) {
value = value || "";
return value.replace(attrs.suffix, "");
});
}
}
});
Apply it to your email field:
<input type="email" name="myfield" ng-required="options.required" ng-model="ngModel" cs-radio-field-format suffix="{{options.suffix}}"/>