WisdomDate

class WisdomDate(val epochMillis: Long) : Number

A date value backed by epoch milliseconds.

It behaves as a Number for every numeric path (arithmetic operators, comparisons, year/month/day, dateAdd/dateSubtract), so existing date math is unchanged. The only difference from a raw Long is how it renders as text: it stringifies to an ISO-8601 instant (e.g. 2026-01-08T00:00:00Z) instead of leaking the raw epoch millis, matching the spec-compliant iOS behavior when a date flows into concat/text output.