Require one attribute between choices in directive - angularjs

Question

I am creating an angular directive and I want the user to specify a 'type' of the directive.
For example:
<my-directive type-a></my-directive>
or
<my-directive type-b></my-directive>
or
<my-directive type-c></my-directive>
I know I can do:
<my-directive type="a"></my-directive>
and then require the type attribute but then I'm doing string matching. Is there anyway to do this by requiring one of 'type-a', 'type-b', or 'type-c' to be present?

Answer 1

Without much background info, I came up with this solution.
JSFIDDLE
So basically myDirective has a controller which is shared by type directives (type-a, type-b.. and so on). The type directive sets the type on the scope of myDirective.
myApp.directive('myDirective', function() {
return {
restrict: 'E',
controller: function($scope) {
$scope.type = '';
this.setType = function(type){
if($scope.type === '') $scope.type = type;
else throw 'type can be only defined once. Current type is '+$scope.type
}
},
link: function(scope, elem, attrs) {
console.log(scope.type);
}
}
});
myApp.directive('typeA', function() {
return {
restrict: 'A',
require: '^myDirective',
link: function(scope, elem, attrs, ctrl) {
ctrl.setType('typeA');
}
}
});
myApp.directive('typeB', function() {
return {
restrict: 'A',
require: '^myDirective',
link: function(scope, elem, attrs, ctrl) {
ctrl.setType('typeB');
}
}
});

Answer 2

I think you can do <div data-my-directive="a"></div> which is a lot safer for cross-browser and w3c. Then the directive would be something like:
.directive('myDirective', function() {
return {
restrict: 'A',
scope: {
type: '='
},
link: function(scope,element,attrs){
}
};
});