Bug report
Describe the bug
Setting NODE_ENV to 'staging' causes next build
to fail on a Webpack "unexpected token" error - presumably the first time it encounters JSX.
To Reproduce
- Create a Next.js app with JSX in it
NODE_ENV=staging npm run build
- ?????
- Failure
Expected behavior
Probably shouldn't fail.
Screenshots

System information
- OS: macOS, whatever Linux Heroku runs
- Version of Next.js: 9.2.0
Additional context
Add any other context about the problem here.