format and parse Temporal (PlainDate, PlainTime, PlainDateTime, ZonedDateTime) using date-fns-style tokens, with real validation — bad input throws instead of silently returning garbage. Locale-aware, no deps.
Timezone-safe date-only (YYYY-MM-DD) parsing, formatting, and math. Zero dependencies. A date is three plain integers, never an instant, so the off-by-one-day bug cannot happen.
Add a description, image, and links to the plaindate topic page so that developers can more easily learn about it.
To associate your repository with the plaindate topic, visit your repo's landing page and select "manage topics."