Watching for when the state changes in the AngularJS framework using the `$scope.$on('$stateChangeStart')` and

Question

Watching for when the state changes in the AngularJS framework using the `$scope.$on('$stateChangeStart')` and

My AngularJs application has the functionality to detect a change in state (using ui.router) and prompt the user to save any unsaved changes. Currently, I am utilizing a confirm dialog for this task:

$scope.$on('$stateChangeStart', () => {
    if (self.changed && confirm('There are unsaved changes. Do you want to save them?'))
        this.save();
});

I have been looking into switching to using the $modal dialog from the bootstrap UI library. However, I encountered an issue where the $modal.open() call is asynchronous and returns immediately, causing the state to change before the dialog can open.

$scope.$on('$stateChangeStart', () => {
    if (self.changed)
       this.$dialog.open({...}).result.then(()=>{
            this.save();
        });
});

I am wondering if there is a solution to prevent this problem or if I should stick with the plain JavaScript confirm dialog?

angularjs twitter-bootstrap dialog typescript angular-ui-router

Answer 1

Answer №1

In tackling the issue at hand, I devised a solution within my application that involves utilizing an AppCtrl (parent) to manage navigation and dirty state concerns.

    function AppCtrl($rootScope, events, modalDialog) {
       var vm = this,
           handlingUnsavedChanges = false;

       function isDirty() {
            return $rootScope.$broadcast(events.CAN_DEACTIVATE).defaultPrevented;
       }

       function onStateChangeStart(event, toState, toParams) {
            if (handlingUnsavedChanges) {
                // continue with state change if dirty state has already been checked
                return;
            }

            // check for dirty state
            if (isDirty()) {
                // prevent navigation
                event.preventDefault();
                modalDialog
                    .confirmNavigation()
                    .then(function () {
                        // ignore changes
                        handlingUnsavedChanges = true;
                        $state.go(toState.name, toParams);
                    });
            } 
            // Otherwise allow state change
        }

        $rootScope.$on('$stateChangeStart', onStateChangeStart);
    }

<div ng-controller="AppCtrl as app">
   <div ui-view />
</div>

Subsequently, you can incorporate an event handler for the CAN_DEACTIVATE event within your route controller to assess dirty states:

    function UserDetailCtrl($scope, events) {
        function isDirty() {
            // Implement your logic to return a boolean value
        }

        function canDeactivate(e) {
            if (isDirty()) {
                e.preventDefault();
            }
        }

        $scope.$on(events.CAN_DEACTIVATE, canDeactivate);
    }

Answer 2

In tackling the issue at hand, I devised a solution within my application that involves utilizing an AppCtrl (parent) to manage navigation and dirty state concerns.

    function AppCtrl($rootScope, events, modalDialog) {
       var vm = this,
           handlingUnsavedChanges = false;

       function isDirty() {
            return $rootScope.$broadcast(events.CAN_DEACTIVATE).defaultPrevented;
       }

       function onStateChangeStart(event, toState, toParams) {
            if (handlingUnsavedChanges) {
                // continue with state change if dirty state has already been checked
                return;
            }

            // check for dirty state
            if (isDirty()) {
                // prevent navigation
                event.preventDefault();
                modalDialog
                    .confirmNavigation()
                    .then(function () {
                        // ignore changes
                        handlingUnsavedChanges = true;
                        $state.go(toState.name, toParams);
                    });
            } 
            // Otherwise allow state change
        }

        $rootScope.$on('$stateChangeStart', onStateChangeStart);
    }

<div ng-controller="AppCtrl as app">
   <div ui-view />
</div>

Subsequently, you can incorporate an event handler for the CAN_DEACTIVATE event within your route controller to assess dirty states:

    function UserDetailCtrl($scope, events) {
        function isDirty() {
            // Implement your logic to return a boolean value
        }

        function canDeactivate(e) {
            if (isDirty()) {
                e.preventDefault();
            }
        }

        $scope.$on(events.CAN_DEACTIVATE, canDeactivate);
    }

Answer 3

Answer №2

Using ui-router and configuration settings in the run section of your app is a great way to achieve this.

The key element here is monitoring the

$rootScope.$on('$stateChangeStart')

event. I have provided a detailed solution on Plunker: http://plnkr.co/edit/RRWvvy?p=preview. The core code can be found in scipt.js, and it looks like this:

routerApp.run(function($rootScope, $uibModal, $state) {
  $rootScope.modal = false; // Setting this ensures that the modal is not constantly loaded, skipping the initial application entrance

  $rootScope.$on('$stateChangeStart',
    function(event, toState, toParams, fromState, fromParams) {

      if ($rootScope.modal) {
        event.preventDefault(); // Stops the transition
        $rootScope.modal = false;
        var modalInstance = $uibModal.open({
          templateUrl: 'modal.html'
        });

        modalInstance.result.then(function(selectedItem) {
          console.log('Changing state to:' + toState.name);
          $state.go(toState, {}, {reload:true});
        }, function() {
          console.log('Going back to state:' + fromState.name);
          $state.go(fromState, {}, {reload:true});
        });
      } else {
        $rootScope.modal = true;
      }
    });
});

Answer 4

Using ui-router and configuration settings in the run section of your app is a great way to achieve this.

The key element here is monitoring the

$rootScope.$on('$stateChangeStart')

event. I have provided a detailed solution on Plunker: http://plnkr.co/edit/RRWvvy?p=preview. The core code can be found in scipt.js, and it looks like this:

routerApp.run(function($rootScope, $uibModal, $state) {
  $rootScope.modal = false; // Setting this ensures that the modal is not constantly loaded, skipping the initial application entrance

  $rootScope.$on('$stateChangeStart',
    function(event, toState, toParams, fromState, fromParams) {

      if ($rootScope.modal) {
        event.preventDefault(); // Stops the transition
        $rootScope.modal = false;
        var modalInstance = $uibModal.open({
          templateUrl: 'modal.html'
        });

        modalInstance.result.then(function(selectedItem) {
          console.log('Changing state to:' + toState.name);
          $state.go(toState, {}, {reload:true});
        }, function() {
          console.log('Going back to state:' + fromState.name);
          $state.go(fromState, {}, {reload:true});
        });
      } else {
        $rootScope.modal = true;
      }
    });
});

Answer 5

Answer №3

To handle unsaved changes, it is important to listen for the $locationChangeStart event in your Angular application. If there are unsaved changes present, make sure to use event.preventDefault() before proceeding with your confirmation dialog using ui-bootstrap modal. Keep in mind that the order of events may vary in different versions of Angular, so relying on the $stateChangeStart event might not be sufficient. I can provide a working example if you run into any issues. Here's a snippet of code to get you started:

$scope.$on('$locationChangeStart', () => {
    if (self.changed) {
       event.preventDefault();
       this.$dialog.open({...}).result.then(()=>{
            this.save();
            // Add logic here for redirection after saving
        });
    }
});

Answer 6

To handle unsaved changes, it is important to listen for the $locationChangeStart event in your Angular application. If there are unsaved changes present, make sure to use event.preventDefault() before proceeding with your confirmation dialog using ui-bootstrap modal. Keep in mind that the order of events may vary in different versions of Angular, so relying on the $stateChangeStart event might not be sufficient. I can provide a working example if you run into any issues. Here's a snippet of code to get you started:

$scope.$on('$locationChangeStart', () => {
    if (self.changed) {
       event.preventDefault();
       this.$dialog.open({...}).result.then(()=>{
            this.save();
            // Add logic here for redirection after saving
        });
    }
});

Answer 7

Answer №4

If you are looking to handle state change events, it is recommended to implement the event on the app and utilize the $modal service. For a more detailed explanation, you can refer to the following link:

While the example provided works for all state changes, you have the option to customize it for specific states as shown below:

app.run(function ($rootScope) {

  $rootScope.$on('$stateChangeStart', function (event, toState, toParams) {
  if(toState.name =="desiredState") {
  event.preventDefault();
  // add your custom logic here
  }
  });

});

Answer 8

If you are looking to handle state change events, it is recommended to implement the event on the app and utilize the $modal service. For a more detailed explanation, you can refer to the following link:

While the example provided works for all state changes, you have the option to customize it for specific states as shown below:

app.run(function ($rootScope) {

  $rootScope.$on('$stateChangeStart', function (event, toState, toParams) {
  if(toState.name =="desiredState") {
  event.preventDefault();
  // add your custom logic here
  }
  });

});

Answer 9

Answer №5

As I am not very familiar with utilizing the broadcast feature, I adopted a different method.

Instead of using it, I decided to cancel the current event (state change) before displaying my JQuery Dialog. If the user chooses 'yes', then I trigger $state.go. If they choose 'cancel/no', we do not need to take any action as we have already canceled the event.

$rootScope.$on('$stateChangeStart',function (event, toState, toParams, fromState, fromParams, options) {

    console.log('$stateChangeStart- fromState= '+fromState.name +'-toState= '+toState.name);

    /*When a user attempts to change the state, a confirmation dialog is displayed
     * Selecting 'Yes' will proceed with the state change and enter pause mode for collection.
     * Choosing 'No' will halt the state change process.
     */
    if (/*some condition*/) {                    

        /*Avoids an additional cycle of listening to stateChangeStart
        when stateChangeStart gets triggered again by $state.go initiated from our modal dialog*/
        if (service.stateChangeTriggeredByDialog) {
            service.stateChangeTriggeredByDialog = false;
            return;
        }

        if (fromParams.paramName !== toParams.paramName) {
            event.preventDefault();                        

            Dialog.confirm({
                dialogClass: 'my-customDialog',
                template: $translate.instant('STATE_CHANGE_MSG'),
                resizable: false,
                width: 550                            
            }).then(function () {   
                console.log('User chose to continue with the state change');  
                service.stateChangeTriggeredByDialog = true;
                $state.go(toState, toParams, { inherit: false });
            }, function () {
                console.log('User chose to stop the state change');                            
            });                                            
        }
    }});

Answer 10

As I am not very familiar with utilizing the broadcast feature, I adopted a different method.

Instead of using it, I decided to cancel the current event (state change) before displaying my JQuery Dialog. If the user chooses 'yes', then I trigger $state.go. If they choose 'cancel/no', we do not need to take any action as we have already canceled the event.

$rootScope.$on('$stateChangeStart',function (event, toState, toParams, fromState, fromParams, options) {

    console.log('$stateChangeStart- fromState= '+fromState.name +'-toState= '+toState.name);

    /*When a user attempts to change the state, a confirmation dialog is displayed
     * Selecting 'Yes' will proceed with the state change and enter pause mode for collection.
     * Choosing 'No' will halt the state change process.
     */
    if (/*some condition*/) {                    

        /*Avoids an additional cycle of listening to stateChangeStart
        when stateChangeStart gets triggered again by $state.go initiated from our modal dialog*/
        if (service.stateChangeTriggeredByDialog) {
            service.stateChangeTriggeredByDialog = false;
            return;
        }

        if (fromParams.paramName !== toParams.paramName) {
            event.preventDefault();                        

            Dialog.confirm({
                dialogClass: 'my-customDialog',
                template: $translate.instant('STATE_CHANGE_MSG'),
                resizable: false,
                width: 550                            
            }).then(function () {   
                console.log('User chose to continue with the state change');  
                service.stateChangeTriggeredByDialog = true;
                $state.go(toState, toParams, { inherit: false });
            }, function () {
                console.log('User chose to stop the state change');                            
            });                                            
        }
    }});

Watching for when the state changes in the AngularJS framework using the `$scope.$on('$stateChangeStart')` and

Answer №1

Answer №2

Answer №3

Answer №4

Answer №5

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