missing date patch

[scampi]

closes #4693

[elasticsearch-release]

Jenkins standing by to test this. If you aren't a maintainer, you can ignore this comment. Someone with commit access, please review this and clear it for Jenkins to run; then say 'jenkins, test it'.

[jbudz]

Looks good @scampi! Two small concerns before merging:

1. Can we make the output for null and undefined dates consistent - the empty string makes sense
2. Add tests for converting null/undefined, https://github.com/elastic/kibana/blob/master/src/ui/public/stringify/__tests__/_string.js is a decent example to model off of

[scampi]

thanks for the review @jbudz. Both points should be ok now.

[jbudz]

jenkins, test it

[jbudz]

Thanks @scampi! One other issue, the test won't run unless it's loaded in https://github.com/elastic/kibana/blob/master/src/ui/public/stringify/__tests__/index.js

[scampi]

oops... added

[jbudz]

jenkins, test it

[jbudz]

LGTM

[scampi]

thanks @jbudz