title: Angular's filter to check if object is empty null or undefined
body: <p>I would like to have a filter that will check if a given json object is empty, null or undefined. Without using any third-party lib.</p>
  
  <pre><code>function isObjValid(obj) {
        return !(obj === undefined || obj === null || Object.keys(obj).length === 0)
    };
  </code></pre>
  
  <p>But when I tried to filter the object from my template :</p>
  
  <pre><code>&lt;ng-if ng-if="$ctrl.data | filter:isObjValid"&gt;
     ...
  &lt;/ng-if&gt;
  </code></pre>
  
  <p>I get this error :</p>
  
  <pre><code>Error: [filter:notarray] Expected array but received: {}
  </code></pre>
  
  <p>Is there any way to avoid <code>notarray</code> ?</p>