title: How to validate the length of character is equals to 5 using express-validator?
body: <p>I am planning to make partnerid field character length as 5 which means user will get error message if he enters less than 5 character or more than 5 characters which will include alpha-numeric character. 
  How can we do it using express-validator?
  I tried using below code but it didn't worked
  Thanks </p>
  
  <pre><code>   req.checkBody('partnerid', 'Partnerid field must be 5 character long ').len(5);
  </code></pre>