Day.js Wrapper - ISO 8601 Week Support & Date Math

I built a lightweight wrapper for Day.js to handle complex date math and fix the ISO week-year mismatch in TiddlyWiki. I discovered that my daily journal entries weren’t getting the correct ISO week for the last days of December, so I wrapped day.js in JavaScript, since it’s modern and lightweight (~2KB).

Usage:

<<dayjs "2024-12-31" "WW-GGGG">>
// Output: 01-2025 (Correct ISO Year)

It supports standard formats (YYYY-MM-DD) and advanced tokens (Do for ordinals, Q for quarters). You can see more examples on my demo TiddlyWiki.

Let me know if there’s anything I can add to improve this wrapper.

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