title: why does 'npm run build' take >30 minutes on development server and less than a minute locally?
body: <p>I am not particularly experienced with either npm or webpack.  I have a fairly small project that builds very quickly locally (much less than a minute), yet takes a ridiculously-long time to run on our test server.</p>
  
  <p>in <code>package.json</code> the code is <code>"scripts": {
      "build": "webpack --config webpack.prod.js", ...</code></p>
  
  <p>Running <code>npm run build</code> executes very quickly on my local development machine. It uses copy-webpack-plugin as described <a href="https://stackoverflow.com/questions/27639005/how-to-copy-static-files-to-build-directory-with-webpack">here</a> to build a directory of static content.</p>
  
  <p>When I attempt to do the same from our test server (after getting exact same files from github), the <code>npm run build</code> command takes well more than half an hour - if it completes at all before I give up and just manually copy over the relevant files from my local dev.</p>