title: How to push the empty JSON data to an array field which is type of Observable<any[]> angular 2
body: <p>I have a variable like,</p>
  
  <pre><code>public categories: Observable&lt;any[]&gt;;
  </code></pre>
  
  <p>So after the service call, the returned data of service call will push an array of JSON data to the field which I mentioned above.</p>
  
  <p>After that, I need to push an empty JSON data to that field. As it is a type of Observable, I can't just directly use <strong>.push</strong> </p>
  
  <p><strong>Is there any solution to push the empty JSON data to an array which is type of Observable?</strong></p>