title: What does var name = ()() do?
body: <p>I encountered the code like below.</p>
  
  <pre><code>return new Promise(function (resolve, reject) {
        if (!message) return reject(new Error('Requires message request to send'));
        message = (0, _getURLJWT)(message);
        .....
        .....
        var enc = (0, _encryptMessage)(plaintext, pubEncKey);
  
        }, function (error, res, body) {
         ....
         ....
        });
      });
  </code></pre>
  
  <p>I do not understand the two expressions in the code:</p>
  
  <pre><code>message = (0, _getURLJWT)(message);
  var enc = (0, _encryptMessage)(plaintext, pubEncKey);
  </code></pre>
  
  <p>This looks like IIFE(Immediately invoked function expression), however, I do not understand how the brackets at the end of the line exactly work or what they are doing.</p>
  
  <p>Could anyone help me understand this?</p>