Lowercase ULIDs should be considered valid ULIDs

[Qrivi]

Hello everyone.

For a project at work our API uses ULIDs. I noticed Zod comes with a ULID validator built in, however, it always marks our ULIDs as invalid. After a short investigation, I learned that only uppercase ULIDs are considered valid by Zod.

I think the regex Zod uses to check ULID validity, should also allow lowercase ULIDs (or even mix of upper and lower case) as the ULID spec indicates they are case insensitive.

The simple workaround we use right now is z.string().toUpperCase().ulid() (we used to use refine() and a custom validation function), but imo it's not ideal as it affects other validation checks and it might be confusing to other users why lowercase ULIDs are considered invalid. wdyt?

I don't mind working on this myself, as I believe it's just updating the regex to be case insensitive and making sure tests still succeed.

[mohamed-azd]

Hello ! I have modified the ULID regex to make it case insensitive.

Here is the PR

[dosubot]

Hi, @Qrivi. I'm Dosu, and I'm helping the Zod team manage their backlog. I'm marking this issue as stale.

Issue Summary:

• You raised an issue about Zod's ULID validator only accepting uppercase ULIDs.
• You suggested updating the regex to accommodate lowercase or mixed-case ULIDs.
• Mohamed-azd modified the ULID regex to be case-insensitive and submitted a pull request.
• You positively reacted to the pull request, indicating the issue was resolved.

Next Steps:

• Please confirm if this issue is still relevant to the latest version of the Zod repository. If so, you can keep the discussion open by commenting here.
• Otherwise, this issue will be automatically closed in 7 days.

Thank you for your understanding and contribution!