Detecting and using a changed controller dependency during controller lifetime - angularjs

Question

For the sake of understanding suppose I have an AngularJS application that has similar data as Stackoverflow so that it:
is using the usual ngRoute/$routeProvider
has a userService that returns favourite and ignore tag lists of the logged in user - both lists are fetched at the same time and request for them is a promise that when resolved caches these lists
has a view that displays a list of questions with a QuestionsController that provides its model (similar to Stackoverflow)
QuestionsController makes a request for questions and then depends on cached tag lists to mark them appropriately
As the recommended guideline when controllers rely on other async data we should offload those to route resolve part so when controllers are being instantiated those promises are already resolved. Therefore I offload tag list fetching to it so both lists are ready and injected into the controller. This all works as expected.
The additional feature of my questions list view is that when a user clicks a tag displayed on questions it automatically adds this tag to favourite list (or off of it when that tag is already part of favourite list).
Route configuration
...
.when({
templateUrl: "...",
controller: "QuestionsController as context",
resolve: {
tags: ["userService", function(userService) {
return userService.getMyTags();
}]
}
})
.when(...)
...
Controller pseudo code
QuestionsController.prototype.markQuestions = function() {
this.model.questions.forEach(function(q, idx) {
// "myTags" is resolve injected dependency
q.isFavourite = q.tags.any(myTags.favourite);
q.isIgnored = q.tags.any(myTags.ignored);
});
};
QuestionsController.prototype.toggleTag = function(tag) {
var self = this;
// change tag subscription
tagService
.toggleFavourite(tag)
.then(function() {
// re-mark questions based on the new set of tags
self.markQuestions();
});
};
The problem
When the view displays, all questions are loaded and correctly marked as per provided tag lists. Now when a user clicks on a specific tag and that tag's favourite status gets changes my controller's dependency should get automatically updated.
How can I do that since my controller is already instantiated and had tag lists injected during instantiation?
I would like to avoid loading those lists manually within my controller because in that case I should do the same during instantiation and reuse the same functionality and not have it in two places (route resolve and inside controller).

Answer 1

So long as your "resolved" variable is referring to the same object used elsewhere, they are one and the same.
So, if your userService.getMyTags is conceptually like the following:
.factory("userService", function($timeout){
var tags = [/*...*/];
return {
getMyTags: function(){
return $timeout(function(){ return tags; }, 500);
},
addTag: function(newTag){
tags.push(newTag);
}
}
});
Then any reference to tags anywhere would get the changes:
.controller("ViewCtrl", function($scope, tags){
$scope.tags = tags; // tags is "resolved" with userService.getMyTags()
})
.controller("AddTagCtrl", function($scope, userService){
$scope.addTag = function(newTag){
userService.addTag(newTag); // changes will be reflected in ViewCtrl
}
}
plunker, to illustrate