I inspect the react code and in call stacks, found `process.env.NODE_ENV` is undefined due to which 'SyntheticEvent.call' is not callable.
So, to fix this, i add 'definePlugin' to plugins for `dev` environment in `webpack.config.js`. Initially it was added only for `production` environment. but it is needed for both, because React code is conditional based on environment variables set.
Please find attached patch and review.
As discussed, you're setting 'production', even in the 'development' mode.
Please understand the code, and share the updated patch.
Also - share the references next time, so that - committer can understand the reason for these changes.
