title: Weird behaviour of request-json with bluebird promise
body: <p>I'm trying to wrap my head around promises, but so far I can't seem to get simple example working. Here it a code to request JSON from the server: </p>
  
  <pre><code>module.exports = function (app, options) {
  var promise = require('bluebird');
  var request = require('request-json');
  
  var module = {
      url: options.url,
      httpClient: promise.promisifyAll(request.createClient(options.url))
  };
  
  module.getSample = function() {
      return this.httpClient.getAsync('sample/')
          .then(function(error, response, body) {
              console.log(body);
          })
          .catch(function(e) {
              console.log('error');
              console.log(e);
          });
  };
  
  return module;
  </code></pre>
  
  <p>};</p>
  
  <p>but when I call it like this:</p>
  
  <pre><code>var backendClient = require('./utils/backendClient.js')(app, {
      url: 'http://localhost:8080/'
  });
  
  backendClient.getSample()
  </code></pre>
  
  <p>at runtime I get an error saying '[SyntaxError: Unexpected token o]'. Version without promises works fine. What did I miss?</p>