title: Google Apps Script - Gmail, delete forever e-mails in trash with specific label
body: <p>I'm trying to make a script that automatically deletes e-mails from a certain sender immediately and permanently, as Gmail only allows for a filter which sends an e-mail to trash for 30 days. Please do not suggest that the default filter is enough, as for my situation, it is vital that I do not know that I was sent an e-mail from this sender.</p>
  
  <p>My current script looks like this:</p>
  
  <pre><code>function deleteForever(labelName) {
      var threads = GmailApp.search("in:trash label:" + labelName);
      for (var i = 0; i &lt; threads.length; i++) {
        threads[i].moveToTrash(); // Where I would need a delete forever trigger
      }
  };
  </code></pre>
  
  <p>However, I have been unable to figure out a way to use a GmailThread and to delete it permanently as there does not exist a function for this purpose. I was looking to see if there was a way I could finish the task using JavaScript, but have been unable figure out a method.</p>
  
  <p>Does anyone have an idea how I can set these e-mails to delete themselves permanently when received?</p>