Having trouble with Angular JS $scope.$apply due to an interpolation error displaying "TypeError: Converting circular structure to JSON"?

Question

Having trouble with Angular JS $scope.$apply due to an interpolation error displaying "TypeError: Converting circular structure to JSON"?

I have created a specialized angular directive shown below:

dirs.directive('sectionInfo', function(){
    return {
        restrict: 'E',
        templateUrl: 'partials/section-home.html',
        transclude: true,
        controller: function($scope, $routeParams){
            var section = this;
            section.sectionItem = [];

            client.entries({"some params"}, 
                function(err, entries){
                    if (err) { console.log(err); return; }
                    $scope.$apply(function(){
                        section.sectionItem = entries;
                });
                }
            );
        },
        controllerAs: 'sectionCtrl'
    }
});

This content is then presented in a distinct partial page that resembles:

<section-info></section-info>
<ul class="list-group">
  <li class="list-group-item" ng-repeat="entry in entriesCtrl.index_items">
    <a href="#/entries/{{entry.sys.id}}">
        <h4>{{entry.fields.title}} <small>{{entry.fields.author}}</small></h4>
    </a>
  </li>
</ul>

The partial template code simply looks like:

{{sectionCtrl.sectionItem}}

Upon loading this page and retaining the $scope$apply call, an error is triggered:

Error: error:interr Interpolation Error Can't interpolate: {{sectionCtrl.sectionItem}} TypeError: Converting circular structure to JSON

If I eliminate the $scope.$apply call, the error disappears. Any insights into what could be causing the circular reference issue within the $scope.$apply call?

EDIT: The content of entries and the error message captured in the console log.

javascript json angularjs

Answer 1

Answer №1

It appears that there is a circular reference issue occurring, where an object is referencing itself through one of its properties or elements. This can be seen in your image, particularly with the sys field pointing back to its parent object. I have provided a sample code snippet below to demonstrate how an object referencing itself through a field can cause errors when attempting to convert it to regular JSON format.

angular.module("so", []);

console.error = function(msg){
  console.log("Well, an error occurred, here's what it said:" + msg);
}

angular.module("so").controller("AnswerCtrl", function($scope){

  // create an object and assign it to itself
  $scope.thing = { somefield: 'lalalala' };
  $scope.thing.circle= $scope.thing;

});

<script src="https://ajax.googleapis.com/ajax/libs/angularjs/1.2.23/angular.min.js"></script>
<div ng-app="so" ng-controller="AnswerCtrl">
  {{ thing }}
</div>

The root of the problem lies not directly with Angular, but rather with how Angular handles converting objects to JSON for display purposes using JSON.stringify. To address this issue, refrain from attempting to serialize cyclic objects to JSON for display.

If you need to display all properties of the object, consider implementing a solution like the one outlined in this answer, as demonstrated below:

angular.module("so", []);

console.error = function(msg){
  console.log("Well, an error occurred, here's what it said:" + msg);
}

angular.module("so").controller("AnswerCtrl", function($scope){

  // create an object and assign it to itself
  $scope.thing = { somefield: 'lalalala' };
  $scope.thing.circle= $scope.thing;

  var cache = [];
  $scope.viewThing = JSON.stringify($scope.thing, function(key, value) {
    if (typeof value === 'object' && value !== null) {
      if (cache.indexOf(value) !== -1) {
        return;
      }
      cache.push(value);
    }
    return value;
  });

});

<script src="https://ajax.googleapis.com/ajax/libs/angularjs/1.2.23/angular.min.js"></script>
<div ng-app="so" ng-controller="AnswerCtrl">
  {{ viewThing }}
</div>

If displaying the object is necessary, consider using this library to handle circular references.

Answer 2

It appears that there is a circular reference issue occurring, where an object is referencing itself through one of its properties or elements. This can be seen in your image, particularly with the sys field pointing back to its parent object. I have provided a sample code snippet below to demonstrate how an object referencing itself through a field can cause errors when attempting to convert it to regular JSON format.

angular.module("so", []);

console.error = function(msg){
  console.log("Well, an error occurred, here's what it said:" + msg);
}

angular.module("so").controller("AnswerCtrl", function($scope){

  // create an object and assign it to itself
  $scope.thing = { somefield: 'lalalala' };
  $scope.thing.circle= $scope.thing;

});

<script src="https://ajax.googleapis.com/ajax/libs/angularjs/1.2.23/angular.min.js"></script>
<div ng-app="so" ng-controller="AnswerCtrl">
  {{ thing }}
</div>

The root of the problem lies not directly with Angular, but rather with how Angular handles converting objects to JSON for display purposes using JSON.stringify. To address this issue, refrain from attempting to serialize cyclic objects to JSON for display.

If you need to display all properties of the object, consider implementing a solution like the one outlined in this answer, as demonstrated below:

angular.module("so", []);

console.error = function(msg){
  console.log("Well, an error occurred, here's what it said:" + msg);
}

angular.module("so").controller("AnswerCtrl", function($scope){

  // create an object and assign it to itself
  $scope.thing = { somefield: 'lalalala' };
  $scope.thing.circle= $scope.thing;

  var cache = [];
  $scope.viewThing = JSON.stringify($scope.thing, function(key, value) {
    if (typeof value === 'object' && value !== null) {
      if (cache.indexOf(value) !== -1) {
        return;
      }
      cache.push(value);
    }
    return value;
  });

});

<script src="https://ajax.googleapis.com/ajax/libs/angularjs/1.2.23/angular.min.js"></script>
<div ng-app="so" ng-controller="AnswerCtrl">
  {{ viewThing }}
</div>

If displaying the object is necessary, consider using this library to handle circular references.

Answer 3

Answer №2

Consider implementing the following solution:

var applySafely = function (scope, func) {
    if (scope.$$phase !== '$apply' && scope.$$phase !== '$digest' &&
        (!scope.$root || (scope.$root.$$phase !== '$apply' && scope.$root.$$phase !== '$digest')))    {
        scope.$apply();
    }
    if (angular.isFunction(func)) {
        func();
    }
};

You can use it like this:

applySafely($scope, function(){
   section.sectionItem = entries;
 });

Answer 4

Consider implementing the following solution:

var applySafely = function (scope, func) {
    if (scope.$$phase !== '$apply' && scope.$$phase !== '$digest' &&
        (!scope.$root || (scope.$root.$$phase !== '$apply' && scope.$root.$$phase !== '$digest')))    {
        scope.$apply();
    }
    if (angular.isFunction(func)) {
        func();
    }
};

You can use it like this:

applySafely($scope, function(){
   section.sectionItem = entries;
 });

Having trouble with Angular JS $scope.$apply due to an interpolation error displaying "TypeError: Converting circular structure to JSON"?

Answer №1

Answer №2

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