subscribed events in durandaljs are not unsubscribed - durandal

Question

This is the flow of the application:
The shell.js loads the schoolyeardialog.js which contains the schoolyearbrowser.js which loads the schoolyearwizard.js via create or edit button.
When I repeat these steps multiple times: click create/edit button then I do multiple
requests in my SchoolyearWizard to this:
$.when(service.editSchoolyear(schoolyearId))
The reason is that the subscribed events are not correctly unsubscribed in my opinion.
I have tried different ways of unsubscribing in the SchoolyearDialog.js file.
Either the events did not fire - when I did the subscription.off(); after the app.on(...)
or It was unsubscribed at the wrong position.
Where should I unsubscribe correctly?
If you guys need a sample repo as visual studio solution I can provide this if it helps or maybe you see clearly and immediately the error?!
I have also thought about unsubscribing from the 2 events create/edit when the SchoolyearDialog module is "unloaded" because then both events could/would be unsubscribed not only the create OR edit subscription as it is now when I either click the add or edit button... how would I do that?
SHELL
define(['plugins/router', 'durandal/app', 'viewmodels/SchoolyearDialog', 'knockout'], function (router, app, schoolyearDialog, ko) {
self.schoolyearIsLoaded = ko.observable(false);
var saveTimeTableSubscription = app.on('savedTimeTable').then(function (options) {
// after coming the 2nd time here
if (!self.schoolyearIsLoaded()) {
router.map([{ route: 'lessonplanner', moduleId: 'viewmodels/lessonplanner', title: 'lesson planner', nav: true },
{ route: 'documentbrowser', moduleId: 'viewmodels/documentbrowser', title: 'document browser', nav: true }])
.buildNavigationModel();
self.schoolyearIsLoaded(true);
}
router.navigate("lessonplanner", true);
});
return {
router: router,
activate: function () {
router.map([{ route: '', moduleId: 'viewmodels/SchoolyearDialog', nav: true, title: 'Schoolyearbrowser' }
]).buildNavigationModel();
return router.activate('SchoolyearDialog');
}
};
});
SchoolyearDialog
define(['durandal/app', 'knockout', 'plugins/router', 'viewmodels/SchoolyearWizard'],
function (app, ko, router, wizard) {
var ctor = function () {
debugger;
var self = this;
self.createSubscribe = ko.observable();
self.editSubscribe = ko.observable();
self.activeScreen = ko.observable('viewmodels/SchoolyearBrowser'); // set the schoolyear browser as default module
var createWizardSubscription = app.on('createWizard').then(function () {
self.createSubscribe().off();
self.createSubscribe(null);
self.activeScreen(new wizard('create'));
}, self);
self.createSubscribe(createWizardSubscription);
var editWizardSubscription = app.on('editWizard').then(function (schoolyearId) {
self.editSubscribe().off();
self.editSubscribe(null);
self.activeScreen(new wizard('edit', schoolyearId));
}, self);
self.editSubscribe(editWizardSubscription);
}
return ctor;
});
SchoolyearBrowser
define(['durandal/app', 'plugins/dialog', 'knockout', 'services/dataservice', 'plugins/router'],
function (app, dialog, ko, dataservice, router) {
var SchoolyearBrowser = function () {
var self = this;
self.schoolyears = ko.observableArray();
$.when(dataservice.getSchoolyears())
.done(function (schoolyearModels) {
self.schoolyears(schoolyearModels);
});
self.create = function () {
app.trigger('createWizard');
}
self.edit = function () {
app.trigger('editWizard', 1);
}
};
return SchoolyearBrowser;
});
SchoolyearWizard
define(['durandal/activator', 'viewmodels/step1', 'viewmodels/step2', 'knockout', 'durandal/app', 'services/dataservice', 'viewmodels/CreateEditSchoolyearViewModel'],
function (activator, Step1, Step2, ko, app, service, CreateEditSchoolyearViewModel) {
var ctor = function (viewMode, schoolyearId) {
debugger;
// depending on the mode I could setup 2 different step modules for create and edit ? and the Wizard has one property called content
if (viewMode === 'edit') {
$.when(service.editSchoolyear(schoolyearId))
.done(function (response) {
debugger;
self.viewModel(new CreateEditSchoolyearViewModel(response));
}).fail(function (error) {
alert(error);
});
}
else if (viewMode === 'create') {
$.when(service.createSchoolyear())
.done(function (response) {
debugger;
self.viewModel(new CreateEditSchoolyearViewModel(response));
}).fail(function (error) {
alert(error);
});
}
var self = this;
var steps = [new Step1(viewMode), new Step2(viewMode)];
var step = ko.observable(0); // Start with first step
self.activeStep = activator.create();
var stepsLength = steps.length;
self.viewModel = ko.observable();
this.hasPrevious = ko.computed(function () {
return step() > 0;
});
self.caption = ko.observable();
this.activeStep(steps[step()]);
this.hasNext = ko.computed(function () {
if ((step() === stepsLength - 1) && self.activeStep().isValid()) {
// save
self.caption('save');
return true;
} else if ((step() < stepsLength - 1) && self.activeStep().isValid()) {
self.caption('next');
return true;
}
});
this.isLastStep = function () {
return step() === stepsLength - 1;
}
this.next = function () {
if (this.isLastStep()) {
var vm = this.activeStep(); //.viewModel;
$.when(service.saveCreateSchoolyear({ schoolyearId: 1 })).done(function () {
app.trigger('savedTimeTable', { isSuccess: true });
}).fail(function (e) {
alert(e);
});
}
else if (step() < stepsLength) {
step(step() + 1);
self.activeStep(steps[step()]);
}
}
this.previous = function () {
if (step() > 0) {
step(step() - 1);
self.activeStep(steps[step()]);
}
}
}
return ctor;
});

Answer 1

This helped me greatly:
activator.deactivate function allows the previous object to execute custom deactivation logic."
SchoolyearDialog.js
self.deactivate = function () {
self.createSubscribe().off();
self.editSubscribe().off();
}
When the schoolyearDialog is deactivated both events are unsubscribed independing wether button create/edit is clicked. This is for me a clean solution :)

Answer 2

I agree with your solution but I'd recommend not to use plain .off() without parameters as this will cause to deregister all the events in the application.
Rather pass the event name as a parameter to your off method:
self.createSubscribe().off('savedTimeTable');