Allow user to set WebpackDevServer watchOptions.poll option for react-scripts start

This could potentially be done by modifying the instantiation of the WebpackDevServer in start.js to look like:

...
watchOptions: {
  ignored: /node_modules/,
  poll: process.env.REACT_APP_POLL || undefined,
}
...

This use case is important to me (and others) because I’m developing in a Docker container, which has issues with inotify (due to mounting volumes with aufs), which precludes the automatic rebuild without the watchOptions poll setting.

[fson]

Chokidar, which Webpack uses for watching changes has an environment to force the use of polling: CHOKIDAR_USEPOLLING. Does this fix the issue with Docker?

CHOKIDAR_USEPOLLING=true npm start

[airtonix]

you know, if all these nodejs people writing cli apps used nconf.env().argv() we’d be able to set configuration through environment variables or command line arguments.