Invoke a Method Directly on a Sibling Directive - angularjs

Question

Is it possible to call a method directly on a specific directive if the ID of that specific directive is known? I know how to do it through listener events (broadcast or emit). I suppose I could do my manipulation using jQuery but I'd like to be able to do it only through Angular. Also, I'd like to avoid the listener event because it seems "wasteful" for every instance of that directive to have to determine if that particular event "belongs" to them.
HTML
<custom-element ce-Id="5"></custom-element>
<custom-element ce-Id="6"></custom-element>
<custom-element ce-Id="7"></custom-element>
<custom-element ce-Id="8"></custom-element>
<custom-element ce-Id="9"></custom-element>
<custom-element ce-Id="10"></custom-element>
So using the example above, is it possible for an event on directive ce-Id="6" (say a click event) to trigger something to happen specifically on ce-Id="7" without using a listener?

Answer 1

You can define a custom API in the factory function of the directive and keep track of subscribers. This code will only run once. Can move it to a service as well.
Example:
app.directive('customElement', function() {
var subscribers = {};
var subscribe = function(id, callback) {
subscribers[id] = callback;
};
var unsubscribe = function(id) {
subscribers[id] = null;
};
var notify = function(id) {
var target = parseInt(id) + 1;
var action = subscribers[target];
if (action) action();
};
var api = {
subscribe: subscribe,
unsubscribe: unsubscribe,
notify: notify
};
return {
restrict: 'E',
template: '<div>I am custom element: {{ ceId }}</div>',
scope: {
ceId: '#',
},
link: function(scope, element, attrs) {
var id = scope.ceId;
if (!id) return;
var onReceive = function() {
console.log('customElement ' + id + ' has received notification.');
};
api.subscribe(id, onReceive);
var onClick = function() {
scope.$apply(function () {
api.notify(id);
});
};
element.on('click', onClick);
scope.$on('$destroy', function() {
element.off('click', onClick);
api.unsubscribe(id);
});
}
};
});
Demo: http://plnkr.co/edit/2s1bkToSuHPURQUcvZcd?p=preview