Detect unsaved changes and alert user using angularjs

Question

Below is the code so far

Answer 1

I modified the @Anders answer so that the directive does not contain the form name hard coded:

    app.directive('confirmOnExit', function() {
        return {
            link: function($scope, elem, attrs, ctrl) {
                window.onbeforeunload = function(){
                    if ($scope[attrs["name"]].$dirty) {
                        return "Your edits will be lost.";
                    }
                }
            }
        };
    });

Here is the html code for it:

<form name="myForm" confirm-on-exit> 

Answer 2

To use Anders Ekdahl's excellent answer with an Angular 1.5 component, inject the $scope in the component's controller:

angular
  .module('myModule')
  .component('myComponent', {
    controller: ['$routeParams', '$scope',
      function MyController($routeParams, $scope) {
        var self = this;

        $scope.$on('$locationChangeStart', function (event, next, current) {
          if (self.productEdit.$dirty && !confirm('There are unsaved changes. Would you like to close the form?')) {
            event.preventDefault();
          }
        });
      }
    ]
  });

Answer 3

I've extended the @Anders answer to clean up listeners (unbind listers) when directive is destroyed (ex: when route changes), and added some syntactic sugar to generalise the usage.

confirmOnExit Directive:

/**
 * @name confirmOnExit
 * 
 * @description
 * Prompts user while he navigating away from the current route (or, as long as this directive 
 * is not destroyed) if any unsaved form changes present.
 * 
 * @element Attribute
 * @scope
 * @param confirmOnExit Scope function which will be called on window refresh/close or AngularS $route change to
 *                          decide whether to display the prompt or not.
 * @param confirmMessageWindow Custom message to display before browser refresh or closed.
 * @param confirmMessageRoute Custom message to display before navigating to other route.
 * @param confirmMessage Custom message to display when above specific message is not set.
 * 
 * @example
 * Usage:
 * Example Controller: (using controllerAs syntax in this example)
 * 
 *      angular.module('AppModule', []).controller('pageCtrl', [function () {
 *          this.isDirty = function () {
 *              // do your logic and return 'true' to display the prompt, or 'false' otherwise.
 *              return true;
 *          };
 *      }]);
 * 
 * Template:
 * 
 *      <div confirm-on-exit="pageCtrl.isDirty()" 
 *          confirm-message-window="All your changes will be lost."
 *          confirm-message-route="All your changes will be lost. Are you sure you want to do this?">
 * 
 * @see
 * http://stackoverflow.com/a/28905954/340290
 * 
 * @author Manikanta G
 */
ngxDirectivesModule.directive('confirmOnExit', function() {
    return {
        scope: {
            confirmOnExit: '&',
            confirmMessageWindow: '@',
            confirmMessageRoute: '@',
            confirmMessage: '@'
        },
        link: function($scope, elem, attrs) {
            window.onbeforeunload = function(){
                if ($scope.confirmOnExit()) {
                    return $scope.confirmMessageWindow || $scope.confirmMessage;
                }
            }
            var $locationChangeStartUnbind = $scope.$on('$locationChangeStart', function(event, next, current) {
                if ($scope.confirmOnExit()) {
                    if(! confirm($scope.confirmMessageRoute || $scope.confirmMessage)) {
                        event.preventDefault();
                    }
                }
            });

            $scope.$on('$destroy', function() {
                window.onbeforeunload = null;
                $locationChangeStartUnbind();
            });
        }
    };
});

Usage: Example Controller: (using controllerAs syntax in this example)

angular.module('AppModule', []).controller('pageCtrl', [function () {
    this.isDirty = function () {
        // do your logic and return 'true' to display the prompt, or 'false' otherwise.

        return true;
    };
}]);

Template:

<div confirm-on-exit="pageCtrl.isDirty()" 
    confirm-message-window="All your changes will be lost." 
    confirm-message-route="All your changes will be lost. Are you sure you want to do this?">

Answer 4

Maybe it will be helpful for someone. https://github.com/umbrella-web/Angular-unsavedChanges

Using this service you can listen unsaved changes for any object in the scope (not only the form)

Answer 5

The accepted answer is great, however I had an issue with properly getting a handle on my form controller consistently since some forms I use the form tag with the name attribute and at other times i use the ng-form directive. Also, if you're using typescript style functions utilizing the this or vm type pattern e.g. <form name='$ctrl.myForm'...

I'm surprised no one else has mentioned this, but my fix was to utilize the require property of the directive and let angular give me a reference to the form controller itself.

I've updated the accepted answer below to show my changes, notice the require property and the additional parameter to the link function.

angular.module("myApp", []).directive('confirmOnExit', function() {
        return {
            restrict: 'A',
            require: 'form',
            link: function($scope, elem, attrs, form) {
                window.onbeforeunload = function(){
                    if (form.$dirty) {
                        return "The form is dirty, do you want to stay on the page?";
                    }
                }
                $scope.$on('$locationChangeStart', function(event, next, current) {
                    if (form.$dirty) {
                        if(!confirm("The form is dirty, do you want to stay on the page?")) {
                            event.preventDefault();
                        }
                    }
                });
            }
        };
    });

With this I can guarantee that I have a good handle on the form controller because angular will throw an error if it cannot find a form controller on the element.

You can also add modifiers like ^ and ? such as require='^form' to pull an ancestor form or require='?form' if the form is optional (this wont break the directive, but you will need to check that you have a handle on a valid form controller yourself).

Answer 6

Something like this should do it:

<!doctype html>
<html ng-app="myApp">
<head>
    <script src="http://code.angularjs.org/1.1.2/angular.min.js"></script>
    <script type="text/javascript">
    function Ctrl($scope) {
        var initial = {text: 'initial value'};
        $scope.myModel = angular.copy(initial);
        $scope.revert = function() {
            $scope.myModel = angular.copy(initial);
            $scope.myForm.$setPristine();
        }
    }

    angular.module("myApp", []).directive('confirmOnExit', function() {
        return {
            link: function($scope, elem, attrs) {
                window.onbeforeunload = function(){
                    if ($scope.myForm.$dirty) {
                        return "The form is dirty, do you want to stay on the page?";
                    }
                }
                $scope.$on('$locationChangeStart', function(event, next, current) {
                    if ($scope.myForm.$dirty) {
                        if(!confirm("The form is dirty, do you want to stay on the page?")) {
                            event.preventDefault();
                        }
                    }
                });
            }
        };
    });
    </script>
</head>
<body>
    <form name="myForm" ng-controller="Ctrl" confirm-on-exit>
        myModel.text: <input name="input" ng-model="myModel.text">
        <p>myModel.text = {{myModel.text}}</p>
        <p>$pristine = {{myForm.$pristine}}</p>
        <p>$dirty = {{myForm.$dirty}}</p>
        <button ng-click="revert()">Set pristine</button>
    </form>
</body>
</html>

Note that the listener for $locationChangeStart isn't triggered in this example since AngularJS doesn't handle any routing in such a simple example, but it should work in an actual Angular application.