title: How can i force angular.js NOT to remove a 0-value from the model?
body: <p>I have a json object containing some properties, whose values can become 0. They are bound to a set of radio buttons (the first ones value is 0). The problem is now, that if i choose the first radio button, the property will be removed by angular.js by default. But i want to keep it with a zero as value.</p>
  
  <p>I also need a way to preselect the first radio button if the value of the bound property is 0/the property doesn't exist. The checked="checked" attribute doesn't work for any reason it the bound value is 0/doesn't exist.</p>
  
  <p>Is there a way to achieve it? Thank you.</p>
  
  <p>The radio buttons:</p>
  
  <pre><code>    &lt;input type="radio" name="type" ng-value="0" ng-model="item.type" 
             ng-init="item.type=0" ng-checked="true"/&gt;
      &lt;input type="radio" name="type" ng-value="1" ng-model="item.type"/&gt;
      &lt;input type="radio" name="type" ng-value="2" ng-model="item.type"/&gt;
      &lt;input type="radio" name="type" ng-value="3" ng-model="item.type"/&gt;
  </code></pre>
  
  <p>The controller:</p>
  
  <pre><code>    $scope.item = {
              type: 0
      };
  </code></pre>