AtemporalModern Date-Time Library

An immutable, chainable wrapper around the Temporal API for easier and safer date-time manipulation.

Temporal API Power

Built on top of the TC39 Stage 4 Temporal API (ES2026) with automatic native-to-polyfill fallback. No extra setup required.

All operations return new instances — no side effects. Fluent API inspired by Day.js for easy-to-read method chaining.

Lightweight core with 8 official plugins. Extend only the functionality you need, or lazy-load plugins on demand.

First-class IANA time zone support. Native Intl integration for seamless i18n — format dates in any locale with full customization.

Built with TypeScript for excellent autocompletion, rich type guards, and comprehensive type definitions.

First-class support for Firebase/Firestore timestamps in both standard and underscore formats. Parse them directly.

Plugin	Description
relativeTime	`.fromNow()` and `.toNow()` support
customParseFormat	Parse complex date strings with custom format tokens
advancedFormat	Ordinal day/quarter suffixes (`Do`, `Qo`), timezone name tokens (`zzz`, `zzzz`)
weekDay	Configurable week start, enhanced weekday handling
durationHumanizer	Convert durations to human-readable, localized strings
dateRangeOverlap	Detect intersections between date ranges with boundary options
businessDays	Working day calculations with holiday and weekend support
timeSlots	Find free time slots in a busy schedule