title: Model is not a date object on input in AngularJS
body: <p>Using AngularJS I am trying to display a date using an input <code>type=date</code>:</p>
  
  <pre><code>&lt;input ng-model="campaign.date_start" type="date"&gt;
  </code></pre>
  
  <p>However, this gives the following error:</p>
  
  <pre><code>Error: error:datefmt
  Model is not a date object
  </code></pre>
  
  <p>The date actually comes from a JSON API in the following format:</p>
  
  <pre><code>date_start": "2014-11-19"
  </code></pre>
  
  <p>I thought that I could resolve it by using a filter, but this did not work and I get the same error with:</p>
  
  <pre><code> &lt;input ng-model="campaign.date_start | date" type="date"&gt;
  </code></pre>
  
  <p>I have also tried converting the string to a date, but again I get the same error:</p>
  
  <pre><code> $scope.campaign.date_start = Date(campaign.date_start);
  </code></pre>
  
  <p>What else can I try?</p>