title: Uncaught TypeError: Converting circular structure to JSON : Backbone
body: <p>I am trying to save a backbone collection like the following : </p>
  
  <pre><code>var backgridModel = Backbone.Model.extend({ });
  
  var BackgridCollection = Backbone.Collection.extend({
      model: backgridModel,
      url : 'api/list'
  });
  
  var backgriCollections = new BackgridCollection();
  backgriCollections.fetch();
  
  var CreatePuppetRequest = Backbone.Model.extend({
      url : 'api/createTable',
      toJSON: function() {
          console.log(backgriCollections.toJSON());
          return backgriCollections.toJSON();
      }
  });
  </code></pre>
  
  <p>I make the server call like the following : </p>
  
  <pre><code>var puppetTable = new CreatePuppetRequest();
  puppetTable.save({}, {
      success : function(model, response) {
          alert("Successfully submitted " + num + " puppet(s)");
          puppetFinalCollection.reset();
          $('#create-puppet-table-button').removeAttr("disabled");
      },
      error : function(model, response) {
          if (response.status == 400)
              that.showErrors($.parseJSON(response["responseText"]));
          else
              console.log(response["responseText"]);
          puppetFinalCollection.reset();
          $('#create-puppet-table-button').removeAttr("disabled");
      }
  });
  </code></pre>
  
  <p><strong>Console output</strong></p>
  
  <pre><code>0: Object
  designation: "m"
  firstName: "sdfghj"
  function (){ return parent.apply(this, arguments); }: Object
  lastName: "sdfghj"
  __proto__: Object
  length: 1
  __proto__: Array[0]
  </code></pre>
  
  <p><code>function (){ return parent.apply(this, arguments); }: Object</code> is added extra to model that I don't know why it is added?</p>
  
  <p>Added to this I get this <code>Uncaught TypeError: Converting circular structure to JSON</code> which blocks the server call too.</p>
  
  <p><strong>EDIT</strong></p>
  
  <p>after fetch() from the server my data would look like the following JSON string :</p>
  
  <pre><code>[
      {
          "userid": "",
          "firstName": "Mayank",
          "lastName": "Kumar",
          "designation": "Software Engineer"
      },
      {
          "userid": "",
          "firstName": "Shylendra",
          "lastName": "Bhat",
          "designation": "Software Engineer"
      },
      {
          "userid": "",
          "firstName": "Akash",
          "lastName": "Waran",
          "designation": "Software Engineer"
      },
      {
          "userid": "",
          "firstName": "Shreyas",
          "lastName": "Lokkur",
          "designation": "Software Engineer"
      },
      {
          "userid": "",
          "firstName": "Anthony",
          "lastName": "Raj",
          "designation": "Software Engineer"
      },
      {
          "userid": "",
          "firstName": "Dheemanth",
          "lastName": "Bharadwaj",
          "designation": "Software Engineer"
      },
      {
          "userid": "",
          "firstName": "Prasanna",
          "lastName": "Adiga",
          "designation": "Software Engineer"
      }
  ]
  </code></pre>
  
  <p>and it is being populated to table too.</p>