Angularjs – Combating AngularJS executing controller twice

angularjs

I understand AngularJS runs through some code twice, sometimes even more, like $watch events, constantly checking model states etc.

However my code:

function MyController($scope, User, local) {

var $scope.User = local.get(); // Get locally save user data

User.get({ id: $scope.User._id.$oid }, function(user) {
  $scope.User = new User(user);
  local.save($scope.User);
});

//...

Is executed twice, inserting 2 records into my DB. I'm clearly still learning as I've been banging my head against this for ages!

Best Answer

The app router specified navigation to MyController like so:

$routeProvider.when('/',
                   { templateUrl: 'pages/home.html',
                     controller: MyController });

But I also had this in home.html:

<div data-ng-controller="MyController">

This digested the controller twice. Removing the data-ng-controller attribute from the HTML resolved the issue. Alternatively, the controller: property could have been removed from the routing directive.

This problem also appears when using tabbed navigation. For example, app.js might contain:

  .state('tab.reports', {
    url: '/reports',
    views: {
      'tab-reports': {
        templateUrl: 'templates/tab-reports.html',
        controller: 'ReportsCtrl'
      }
    }
  })

The corresponding reports tab HTML might resemble:

<ion-view view-title="Reports">
  <ion-content ng-controller="ReportsCtrl">

This will also result in running the controller twice.

Related Solutions

Javascript – Can one AngularJS controller call another

There are multiple ways how to communicate between controllers.

The best one is probably sharing a service:

function FirstController(someDataService) 
{
  // use the data service, bind to template...
  // or call methods on someDataService to send a request to server
}

function SecondController(someDataService) 
{
  // has a reference to the same instance of the service
  // so if the service updates state for example, this controller knows about it
}

Another way is emitting an event on scope:

function FirstController($scope) 
{
  $scope.$on('someEvent', function(event, args) {});
  // another controller or even directive
}

function SecondController($scope) 
{
  $scope.$emit('someEvent', args);
}

In both cases, you can communicate with any directive as well.

Javascript – Insert HTML into view from AngularJS controller

For Angular 1.x, use ng-bind-html in the HTML:

<div ng-bind-html="thisCanBeusedInsideNgBindHtml"></div>

At this point you would get a attempting to use an unsafe value in a safe context error so you need to either use ngSanitize or $sce to resolve that.

$sce

Use $sce.trustAsHtml() in the controller to convert the html string.

 $scope.thisCanBeusedInsideNgBindHtml = $sce.trustAsHtml(someHtmlVar);

ngSanitize

There are 2 steps:

include the angular-sanitize.min.js resource, i.e.:

<script src="lib/angular/angular-sanitize.min.js"></script>

In a js file (controller or usually app.js), include ngSanitize, i.e.:

angular.module('myApp', ['myApp.filters', 'myApp.services', 
    'myApp.directives', 'ngSanitize'])