Bugfix/w should support null values

[RafalKornel]

This PR fixes bug from https://github.com/justin-schroeder/arrow-js/issues/9

Additional typeguards have been added, for handling null values, alongside test cases for bug reproduction and basic w use case

[vercel[bot]]

The latest updates on your projects. Learn more about Vercel for Git ↗︎

Name	Status	Preview	Updated
arrow-js	✅ Ready (Inspect)	Visit Preview	Nov 19, 2022 at 10:52PM (UTC)

[justin-schroeder]

Thanks! @RafalKornel — if you’re up for it, mind shooting me an email at justin@formkit.com? Would love to follow up on something.