title: Uncaught ReferenceError: module is not defined using React and babel
body: <p>When running my app on my localhost, everything works fine, but when I deploy to Heroku, on an onClick event, I get a Chrome DevTools error: <code>Uncaught ReferenceError: module is not defined</code>.</p>
  
  <p>It appears that this line in my compiled js file is creating this error: </p>
  
  <pre><code>function(e) {
          void 0 === module || void 0 === module.exports ? t.jsfeat = e : module.exports = e
      }
  </code></pre>
  
  <p>I certainly want to fix it, but I don't understand why it works when I run my app on localhost but does not work once deployed.  </p>
  
  <p>I am using Node, Express, React, and PostgreSQL, compiling with babel. In searching the issue, it seems like it may be a webpack/babel setup issue, and for some reason it is not compiling correctly?</p>
  
  <p>My deployed app (that doesn't work when clicking 'start'!): <a href="https://dev-eq.herokuapp.com/learn" rel="nofollow noreferrer">https://dev-eq.herokuapp.com/learn</a> 
  My code: <a href="https://github.com/wallacepreston/eq-dev" rel="nofollow noreferrer">https://github.com/wallacepreston/eq-dev</a> </p>