Accessing and manipulating a scope variable in Angular from an external source

Question

Accessing and manipulating a scope variable in Angular from an external source

Can you update a $scope variable in a controller from an external source?

For instance, suppose we have the following controller:

app.controller('citySelectCtrl', ['$scope',function($scope){

}]);

And there is a function in the global scope with an event handler. Now, is it possible to change a $scope variable when that event occurs? Here's our global function:

function initAutocomplete() {
    autocomplete = new google.maps.places.Autocomplete(
        /** @type {!HTMLInputElement} */(document.getElementById('autocomplete')),
        {
            componentRestrictions: {'country': 'in'},
            types: ['(cities)']
        });
    map = new google.maps.Map(document.getElementById('map'), {
        center: {lat: 22.5937, lng: 78.9629},
        zoom: 5,
        minZoom: 5
    });
}

autocomplete.addListener('place_changed', function() {
    infowindow.close();
    marker.setVisible(false);
    var place = autocomplete.getPlace();
    if (!place.geometry) {
      window.alert("Autocomplete's returned place contains no geometry");
      return;
    }

    // If the place has a geometry, then present it on a map.
    if (place.geometry.viewport) {
      map.fitBounds(place.geometry.viewport);
    } else {
      map.setCenter(place.geometry.location);
      map.setZoom(17);  // Why 17? Because it looks good.
    }
----------------------------------------------------------
    //UPDATE $scope.city = place here
----------------------------------------------------------
    infowindow.setContent('<div><strong>' + place.name + '</strong><br>' + address);
    infowindow.open(map, marker);
  });

javascript angularjs

Answer 1

Answer №1

Utilizing $injector allows us to access Angular Services Outside of Scope. Consider this example:

// If the place has a geometry, then present it on a map.
if (place.geometry.viewport) {
  map.fitBounds(place.geometry.viewport);
} else {
  map.setCenter(place.geometry.location);
  map.setZoom(17);  // Why 17? Because it looks good.
}
----------------------------------------------------------
    var elem = angular.element(document.querySelector('[ng-app]'));
    var injector = elem.injector();
     var $rootScope = injector.get('$rootScope');   
     $rootScope.$apply(function(){
       $rootScope.city = place //or city;
     });
----------------------------------------------------------
infowindow.setContent('<div><strong>' + place.name + '</strong><br>' + address);
infowindow.open(map, marker);
});

In your controller, you could include:

app.controller('citySelectCtrl', ['$scope','$rootScope',
    function ($scope,$rootScope) {         
         $rootScope.city = {};

    }
]);

DEMO

For more information, please visit this link

We hope this explanation proves useful.

Answer 2

Utilizing $injector allows us to access Angular Services Outside of Scope. Consider this example:

// If the place has a geometry, then present it on a map.
if (place.geometry.viewport) {
  map.fitBounds(place.geometry.viewport);
} else {
  map.setCenter(place.geometry.location);
  map.setZoom(17);  // Why 17? Because it looks good.
}
----------------------------------------------------------
    var elem = angular.element(document.querySelector('[ng-app]'));
    var injector = elem.injector();
     var $rootScope = injector.get('$rootScope');   
     $rootScope.$apply(function(){
       $rootScope.city = place //or city;
     });
----------------------------------------------------------
infowindow.setContent('<div><strong>' + place.name + '</strong><br>' + address);
infowindow.open(map, marker);
});

In your controller, you could include:

app.controller('citySelectCtrl', ['$scope','$rootScope',
    function ($scope,$rootScope) {         
         $rootScope.city = {};

    }
]);

DEMO

For more information, please visit this link

We hope this explanation proves useful.

Answer 3

Answer №2

If you want to inform your controller about an event, one approach is to utilize $broadcast from the $rootscope.

//rootscope
$rootscope.$broadcast("myevent",eventObjectToBePassed);

//your controller
$scope.$on("myevent",function(eventObject){

//perform actions

});

Another method could involve injecting rootscope into a service and creating a sendEvent function to handle the $rootscope.$broadcast more neatly.

Answer 4

If you want to inform your controller about an event, one approach is to utilize $broadcast from the $rootscope.

//rootscope
$rootscope.$broadcast("myevent",eventObjectToBePassed);

//your controller
$scope.$on("myevent",function(eventObject){

//perform actions

});

Another method could involve injecting rootscope into a service and creating a sendEvent function to handle the $rootscope.$broadcast more neatly.

Answer 5

Answer №3

When working with Angular apps, it is not advisable to directly use global scope variables. The recommended approach is to encapsulate this functionality in a directive and then utilize the directive in your templates. This way, you will have access to the $scope for updating the value. For example:

angular.directive('mapAutoComplete', function () {
  return {
    restrict: 'E',
    link: function (scope, elem, attr) {
      // Implement your map and autocomplete functionality here

      // You can now utilize the `scope` to update the $scope of the parent controller
    }
  }
});

In your HTML, incorporate the directive as follows:

<map-auto-complete></map-auto-complete>

This will enable the scope from the controller of the containing view to be accessible as scope within the directive.

For guidance on using directives instead of direct DOM manipulation and creating reusable functionality, refer to these resources:

Answer 6

When working with Angular apps, it is not advisable to directly use global scope variables. The recommended approach is to encapsulate this functionality in a directive and then utilize the directive in your templates. This way, you will have access to the $scope for updating the value. For example:

angular.directive('mapAutoComplete', function () {
  return {
    restrict: 'E',
    link: function (scope, elem, attr) {
      // Implement your map and autocomplete functionality here

      // You can now utilize the `scope` to update the $scope of the parent controller
    }
  }
});

In your HTML, incorporate the directive as follows:

<map-auto-complete></map-auto-complete>

This will enable the scope from the controller of the containing view to be accessible as scope within the directive.

For guidance on using directives instead of direct DOM manipulation and creating reusable functionality, refer to these resources:

Answer 7

Answer №4

There are a couple of methods that come to mind for achieving this

Utilize the $rootScope as a simple solution. However, I tend to avoid this approach unless absolutely necessary due to it potentially overusing global variables.
Create an Eventhandler and have the controller listen for events

Answer 8

There are a couple of methods that come to mind for achieving this

Utilize the $rootScope as a simple solution. However, I tend to avoid this approach unless absolutely necessary due to it potentially overusing global variables.
Create an Eventhandler and have the controller listen for events

Answer 9

Answer №5

Here is an example of how you can utilize $rootScope:

app.controller('locationController', ['$scope', '$rootScope', function($scope, $rootScope){
    //$rootScope.location = your location;
}]);

You can then access the variable in a global function like this:

function initializeMap() {
    //$rootScope.location = your location;
}

Answer 10

Here is an example of how you can utilize $rootScope:

app.controller('locationController', ['$scope', '$rootScope', function($scope, $rootScope){
    //$rootScope.location = your location;
}]);

You can then access the variable in a global function like this:

function initializeMap() {
    //$rootScope.location = your location;
}

Answer 11

Answer №6

If you want to access the scope of an element, you can use the following code:

var requiredElemScope = angular.element(ELEMENT_SELECTOR).scope();

. After obtaining the scope, you can set a value to a variable within that scope with this line of code:

requiredElemScope.city = someValue;

In this snippet of code, the term ELEMENT_SELECTOR refers to the DOM selector where the controller is linked.

Answer 12

If you want to access the scope of an element, you can use the following code:

var requiredElemScope = angular.element(ELEMENT_SELECTOR).scope();

. After obtaining the scope, you can set a value to a variable within that scope with this line of code:

requiredElemScope.city = someValue;

In this snippet of code, the term ELEMENT_SELECTOR refers to the DOM selector where the controller is linked.

Accessing and manipulating a scope variable in Angular from an external source

Answer №1

Answer №2

Answer №3

Answer №4

Answer №5

Answer №6

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