Hmmh, strange. Thanks for taking the time. Can you log the contents of process.env and process.env.NODE_ENV e.g. before the if clause in options.js?
See inside the browser when loading the main.js e.g. when using firefox or chrome it will be printed to the console, also you’ll see there, if there are JS errors.
https://getfirebug.com/logging
https://developer.mozilla.org/en-US/docs/Tools/Web_Console