compare

Readable comparisons in place of Temporal.X.compare(a, b) > 0, written either as functions (isBefore(a, b)) or as sentences with is(a).before(b). Supported types are PlainDate, PlainTime, PlainDateTime, PlainYearMonth, ZonedDateTime, and Instant. Both arguments must be the same type.

import { isBefore, isBetween, isSameMoment, latest, ascending } from 'orasna';

const due = Temporal.PlainDate.from('2026-11-06');
const submitted = Temporal.PlainDate.from('2026-11-05');

isBefore(submitted, due); // true
isBetween(Temporal.PlainTime.from('12:00'), Temporal.PlainTime.from('08:00'), Temporal.PlainTime.from('12:00')); // false: end excluded
isBetween(submitted, submitted, due, { bounds: '[]' }); // true; bounds: '[)' (default), '[]', '()', '(]'
latest(submitted, due); // 2026-11-06
[due, submitted].sort(ascending); // [2026-11-05, 2026-11-06]

// Two ZonedDateTimes in different zones can be the same moment
isSameMoment(
  Temporal.ZonedDateTime.from('2026-11-02T14:00[Asia/Manila]'),
  Temporal.ZonedDateTime.from('2026-11-02T06:00[UTC]'),
); // true

Also available: isAfter, isSameOrBefore, isSameOrAfter, earliest, and descending. PlainMonthDay cannot be compared because it has no order without a year.

Chainable is()

If you prefer comparisons that read like a sentence, wrap the first value in is(). This is an extra way to write the same checks; the functions above still work.

import { is } from 'orasna';

is(submitted).before(due); // true, same as isBefore(submitted, due)

is(Temporal.PlainTime.from('12:00')).between(Temporal.PlainTime.from('08:00'), Temporal.PlainTime.from('12:00')); // false

is(Temporal.ZonedDateTime.from('2026-11-02T14:00[Asia/Manila]'))
  .sameMomentAs(Temporal.ZonedDateTime.from('2026-11-02T06:00[UTC]')); // true

is(a) method	Same as
.before(b)	isBefore(a, b)
.after(b)	isAfter(a, b)
.sameOrBefore(b)	isSameOrBefore(a, b)
.sameOrAfter(b)	isSameOrAfter(a, b)
.sameMomentAs(b)	isSameMoment(a, b)
.between(start, end, options?)	isBetween(a, start, end, options?)

Each method returns the same result and throws the same errors as its function. is() checks the wrapped value right away, so is('2026-11-02') throws UNSUPPORTED_TYPE before any method is called.