title: create-react-app .env: process not defined
body: <p>create-react-app is supposed to inject your <code>.env</code> variables into your React app. I have used the <code>REACT_APP_</code> prefix with my variables in my <code>.env</code> and <code>.env.development</code>. </p>
  
  <p>However,  when debugging the code I've found that <code>process</code> itself is undefined. So when trying to access an environment variable with <code>process.env.REACT_APP_SOMETHING_URL</code>, the root <code>process</code> variable is undefined. </p>