title: Nightmarejs does not render javascript on server
body: <p>I'm using nightmare for scraping web page, which loads content by javascript after document.ready. I use the following code for receiving html content</p>
  
  <pre><code>.goto(URL)
  .wait('.header--search-icon')
  .evaluate(function () {
      let doc = document.querySelector('body').innerHTML;
      return doc;
  }
  </code></pre>
  
  <p>When I execut this script on my local desctop everything is fine, I receive rendered html.
  However, when I run it on server ubuntu 16.04 I receive javascript content which wasn't rendered.
  I've installed electron and xvfb.
  So, command
  <code>DEBUG=nightmare:* xvfb-run --server-args="-screen 0 1024x768x24" node index.js</code> works fine, but I receive javascript (not html) as a result.
  How can I get result of rendered javascript?</p>