title: 'Maximum call stack size exceeded' from dotenv-expand on CircleCI using React
body: <p>I'm trying to build a react app on CircleCI which until recently I've had no issues with. I'm now getting the following error whenever I attempt an <code>npm run build</code> from my circle.yml:</p>
  
  <pre><code>    #!/bin/bash -eo pipefail
  npm run build
  
  &gt; jobcatcher-web@0.0.1 build /home/circleci/repo
  &gt; react-scripts build
  
  /home/circleci/repo/node_modules/dotenv-expand/lib/main.js:8
        var key = match.replace(/\$|{|}/g, '')
                        ^
  
  RangeError: Maximum call stack size exceeded
      at String.replace (&lt;anonymous&gt;)
      at /home/circleci/repo/node_modules/dotenv-expand/lib/main.js:8:23
      at Array.forEach (&lt;anonymous&gt;)
      at interpolate (/home/circleci/repo/node_modules/dotenv-expand/lib/main.js:7:13)
      at /home/circleci/repo/node_modules/dotenv-expand/lib/main.js:14:18
      at Array.forEach (&lt;anonymous&gt;)
      at interpolate (/home/circleci/repo/node_modules/dotenv-expand/lib/main.js:7:13)
      at /home/circleci/repo/node_modules/dotenv-expand/lib/main.js:14:18
      at Array.forEach (&lt;anonymous&gt;)
      at interpolate (/home/circleci/repo/node_modules/dotenv-expand/lib/main.js:7:13)
  npm ERR! code ELIFECYCLE
  npm ERR! errno 1
  npm ERR! jobcatcher-web@0.0.1 build: `react-scripts build`
  npm ERR! Exit status 1
  npm ERR! 
  npm ERR! Failed at the jobcatcher-web@0.0.1 build script.
  npm ERR! This is probably not a problem with npm. There is likely additional logging output above.
  
  npm ERR! A complete log of this run can be found in:
  npm ERR!     /home/circleci/.npm/_logs/2018-03-14T20_57_45_719Z-debug.log
  Exited with code 1
  </code></pre>
  
  <p>I've tried adding/re-added dotenv-expand dependencies as well as any environmental variables I'm using on CircleCI but with no luck.</p>
  
  <p>Any suggestions? Thanks.</p>