title: How to check variable is either 0 or 1 in express-validator
body: <p>I need to check req.body.isIssueFixed is 0 or 1 , I am trying in epress-validator</p>
  
  <pre><code>req.checkBody(isIssueFixed , 'isIssueFixed  is not a boolean value ').isBoolean();
  </code></pre>
  
  <p>but isBoolean is not an method . How to fix this and where i can chck all the available methods of express-validator ?</p>