title: ERROR in undefined is not iterable! @ multi main
body: <p>After updating some of the packages, my compilation fails. And the error doesn't seems to be very helpful.</p>
  
  <p>I have no clues where the error is. Already tried removing a lot of things, and the errors persists.</p>
  
  <p>I've pushed the project with the issue here: <a href="https://github.com/KadoBOT/reaxor/tree/need-validation" rel="nofollow">https://github.com/KadoBOT/reaxor/tree/need-validation</a></p>
  
  <p>The error appears in two places, in the first line after I <code>npm start</code> and in the last line after the bundle finishes  </p>
  
  <pre><code>(...)
  [0] multi main 64 bytes {0} [built] [1 error]
  [1] (webpack)-dev-server/client?http://localhost:3000 2.67 kB {0} [built]
  [2] ./~/url/url.js 22.3 kB {0} [built]
  (...)
  </code></pre>
  
  <p>And:</p>
  
  <pre><code>(...)
  ERROR in undefined is not iterable!
   @ multi main
  webpack: bundle is now VALID.
  </code></pre>
  
  <p>Anyone experienced the same problem after upgrading packages? How do I solve this, since there is no hint, where the issue is?</p>