modalService cannot talk with controller and view

Question

The code at this plnkr has a modal which pops up when a user clicks on a "Click to take quiz" button which calls a controller method that in turn calls a modal service. To get the plnkr to work, click anywhere in the code and press the space bar to add white space in a way that does not effect syntax. This will trigger plnkr to re-initialize the app and make the modal pop up after you click the button.

The problem is that the text printed in the modal does not update dynamically when timeLeft variable counts down. And also, the user's button click does not update the quizAnswer variable. In short, the modal is not able to talk interactively with the calling controller and view.

What specific changes need to be made to the plnkr to get the modal text to show the dynamic countdown, and to get the modal buttons to change the value of the $scope.quizAnswer variable?

Also, I have been carefully reading the documentation at this link. I think that the answer may be related to:

1.) $uibModal's options parameter passed in open(options) contains the parameter scope that defines the parent scope to be used for the modal's content, and also property bindToController which, when set to true, binds the scope property to a specific controller defined by controllerAs.

2.) The open(options) method returns a modal instance, which includes close(result) and dismiss(reason).

I suspect that the solution lies in these methods and parameters, but I am looking for good examples and would appreciate some experienced eyes looking at this problem.

NOTE: The solution to this came in the comments below the accepted answer, especially the link to another posting that contains 2 lines of code for emitting the modal button click's results back to the parent controller.

Answer 1

You have a number of issues.

First, takeQuiz at navigation.js - line 16, should be attached to $scope, not this, since this will mutate depending on context.

Second, $scope.$apply and $scope.$digst(); at navigation.js - lines 29/30 are unnecessary since you will already be in a digest cycle. They should be removed else they'll trigger an error.

Finally (and this is the meat of your issue), you are misunderstanding how modal options are bound across when creating a modal instance. It is NOT two-way binding; it is a single extends from one object to another. As a result, trying to bind to the options (or creating a concatenated string with the timeRemaining) will not update once it's bound across.

Instead, one possibility is to create an event handler inside of the modal and broadcast on each tick, updating the modal. In addition, if you pass the body text as prepend and append text, it is easier to insert your timestamp value:

You will need to inject (and broadcast from) $rootScope in your navigationController, since the modalService is registered somewhere very high in the scope chain.

On each tick, broadcast the time remaining navigation.js:

$rootScope.$broadcast('timeRemainingTick', $scope.timeRemaining);

In your modalService.js, register to receive the event inside of the controller assignment:

var timeRemainingUnbind = $scope.$on('timeRemainingTick', function(event, newTick) {
    $scope.modalOptions.timeRemaining = newTick;
});

Finally, make sure that you unbind the event by calling timeRemainingUnbind() in the close events of your modal to prevent memory leaks:

$scope.modalOptions.ok = function (result) {
    timeRemainingUnbind();
    $modalInstance.close(result);
};

$scope.modalOptions.close = function (result) {
    timeRemainingUnbind();
    $modalInstance.dismiss('cancel');
};

See my working forked plunker here