title: How to Cronjob to run specific function every 21 days using node-cron node.js
body: <p>I am trying to check the cron to run every 21days. I am getting every 21st day only using the mentioned Cron expression. Can somebody help me to sort this out?</p>
  
  <pre><code>  try {
      var interval = parser.parseExpression('00 12 12 21 * *');
  
      console.log('Date: ', interval.next().toString());
      console.log('Date: ', interval.next().toString());
      console.log('Date: ', interval.next().toString());
      console.log('Date: ', interval.next().toString());
      console.log('Date: ', interval.next().toString());
    } catch (err) {
      console.log('Error: ' + err.message);
    }
  </code></pre>