filter out undefined rules

[williamkunz]

I came across this issue during a Friday (today) prod push, of course. This was a 2 minute fix but has seemingly fixed issue #319

I haven't deep dived into the source so if there is a more elegant fix required, feel free to close.

[williamkunz]

I'll keep digging to see if there is a better solution

[williamkunz]

Upon further digging, 319 may be a non-issue.

From converting Glamor code we had an external string:

import css from 'styled-jsx/css'

export const myStyles = css`
  .my-class: {
    padding: 1.6rem;
  }
`

vs. the correct:

import css from 'styled-jsx/css'

export const myStyles = css`
  .my-class {
    padding: 1.6rem;
  }
`

The extra colon was just leftover from the conversion and causing the same error as described in #319. Maybe this issue should become an optimization with some warning within the css module?

[giuseppeg]

@williamkunz yeah whenever there is a parse error the rule is ignored. This happens only when optimizeForSpeed is enabled (usually automatically for production builds). To prevent surprises in prod you may want to enable optimizeForSpeed manually (via babel plugin options) while you are developing. When optimizeForSpeed is enabled and process.env.NODE_ENV !== 'production' you should get a warning.