Timestamp is designed to work in SSR, SSG, browser, and backend contexts.

The package does not touch window, document, storage APIs, or framework-specific globals. That keeps imports safe during server rendering and static builds.

Server and client timezones

The expected reality is simple: helpers that use the host clock use the timezone of the runtime where they execute.

That means a server in UTC and a browser in America/Edmonton can produce different values if both call today() during render.

For deterministic SSR output:

• Prefer passing explicit timestamps into helpers.
• Use caller-provided now values for relative comparisons.
• Use todayUTC() or nowUTC() when the application wants server and client to agree on UTC calendar fields.
• Use parseDateUTC() when converting native Date instances that represent instants.

import { nowUTC, parseTimestamp, updateRelative } from '@timestamp-js/core'

const now = nowUTC(new Date('2036-06-08T12:00:00.000Z'))
const target = parseTimestamp('2036-06-09')!

const stable = updateRelative(target, now)

If the render needs to be stable even when time passes between server render and client hydration, capture the date once in app code and pass it to nowUTC(date) or todayUTC(date).

Date objects

parseDateUTC(date) reads a native Date using UTC fields. parseDate(date) reads host-local fields.

import { nowUTC, parseDate, parseDateUTC, todayUTC } from '@timestamp-js/core'

const instant = new Date('2036-06-08T09:30:00Z')

const localTimestamp = parseDate(instant)
const utcTimestamp = parseDateUTC(instant)
const dateOnly = todayUTC(instant)
const dateTime = nowUTC(instant)