Passing a callback form directive to controller function in AngularJS - angularjs

Question

I have a directive and a controller. The directive defines a function in its isolate scope. It also references a function in the controller. That function takes a callback. However, when I call it from the directive and pass in a callback, the callback is passed through as undefined. The code below will make this more clear:
Directive
directive('unflagBtn', ["$window", "api",
function($window, api) {
return {
restrict: "E",
template: "<a ng-click='unflag(config.currentItemId)' class='btn btn-default'>Unflag</a>",
require: "^DataCtrl",
scope: {
config: "=",
next: "&"
},
controller: ["$scope",
function($scope) {
$scope.unflag = function(id) {
$scope.next(function() { //this callback does not get passed
api.unflag(id, function(result) {
//do something
return
});
});
};
}
]
};
}
]);
Controller
controller('DataCtrl', ['$rootScope', '$scope', 'api', 'dataManager', 'globals',
function($rootScope, $scope, api, dataManager, globals) {
...
$scope.next = function(cb) { //This function gets called, but the callback is undefined.
// do something here
return cb ? cb() : null;
};
}
]);
HTML
<unflag-btn config="config" next="next(cb)"></unflag-btn>
I've read here How to pass argument to method defined in controller but called from directive in Angularjs? that when passing parameters from directives to controller functions, the parameters need to be passed in as objects. So I tried something like this:
$scope.next({cb: function() { //this callback does not get passed still
api.unflag(id, function(result) {
//do something
return
});
}});
But that did not work. I am not sure if this matters, but I should note that the directive is placed inside a form, which in its place is inside a controller. Just to illustrate the structure:
<controller>
<form>
<directive>
<form>
<controller>
Hope this is clear and thanks in advance!

Answer 1

Try this
controller: ["$scope",
function($scope) {
$scope.unflag = function(id) {
$scope.next({
cb: function() { //this callback does not get passed
api.unflag(id, function(result) {
//do something
return;
});
}
});
};
}
]

Answer 2

So I unintentionally figured out whats wrong after not being able to pass an object back to the controller as well. What happened, (and what I probably should have mentioned in the question had I known that its relevant) is that the parent scope of this directive unflagbtn is actually the scope of another directive that I have, call it secondDirective. In its turn the secondDirective is getting its scope from "DataCtrl". Simplified code looks like this:
directive("secondDirective", [function(){
require: "^DataCtrl" // controller
scope: {
next: "&" // function that I was trying to call
}
...
// other code
...
}]);
directive("unflagbtn", [function(){
require: "^DataCtrl" // controller
scope: {
next: "&"
},
controller: ["$scope", function($scope){
$scope.unflag = function(){
$scope.next({cb: {cb: callBackFunctionIWantedToPass}); // this is what worked
}
}
}]);
So passing a callback in that manner solved my problem as it made its way back to the controller. This is ugly most likely due to my poor understanding of angular, so I apologize as this is most likely not the correct way to do this, but it solved my problem so I though I'd share.
Cheers,