Add datetime using the Temporal API

src/temporal/datetime.js

@@ -0,0 +1,89 @@
+import { weekNumber } from './utils/date.js'
+import { p } from '../utils/string.js'
+import { tzOffset } from '../timezone.js'
+import { config } from '../config/datetime'
+import { Temporal, Intl, toTemporalInstant } from '@js-temporal/polyfill'
+
+Date.prototype.toTemporalInstant = toTemporalInstant
+
+/**
+ * Create `datetime="2021-12-02"` attribute for `<time>`.
+ *
+ * Support all format from the spec.
+ * https://html.spec.whatwg.org/multipage/text-level-semantics.html#attr-time-datetime
+ * https://developer.mozilla.org/en-US/docs/Web/API/HTMLTimeElement/datetime
+ *
+ * See also: https://www.brucelawson.co.uk/2012/best-of-time/
+ *
+ * @param {Date=} date
+ * @param {Precision=} precision
+ * @returns {string}
+ */
+export function datetime(date = new Date(), precision = 'day') {
+  if (!(date instanceof Date)) {
+    throw new TypeError('Input date should be of type `Date`')
+  }
+
+  const instant = date.toTemporalInstant();
+  const zoned = instant.toZonedDateTimeISO(Temporal.Now.timeZoneId())
+
+  const yearISO = y => {
+
+    // Year 0 doesn’t exists in real life, but does in the ISO-8601 spec.
+    const sign = y < 0 ? '-' : '' // no sign if year is not negative
+
+    // Remove sign (stored separately, see previous line).
+    y = Math.abs(y)
+
+    let bigYearDigits = ''
+
+    // Cut last 4 digits of the year from the others to ease further computation.
+    if (y > 9999) {
+      [bigYearDigits, y] = (y / 10000).toFixed(4).split('.')
+    }
+
+    return sign + bigYearDigits + y.toString().padStart(4, 0)
+  }
+
+  // const iso = date.toISOString();
+
+  const temporalFormat = {
+    year: () => yearISO(Temporal.PlainYearMonth.from(zoned).year), // 1960
+    // year: () => date.getFullYear(), // 1960
+    month: () => Temporal.PlainYearMonth.from(zoned), // 1960-04
+    day: () => Temporal.PlainDate.from(zoned), // 1960-04-27
+
+    week: () => date.getFullYear() + '-W' + p(weekNumber(date)), // 1960-W17
+    yearless: () => Temporal.PlainMonthDay.from(zoned), // 04-27
+
+    time: () => Temporal.PlainTime.from(zoned).toString({ smallestUnit: 'minutes' }), // 00:00
+    second: () => Temporal.PlainTime.from(zoned), // 00:00:00
+    ms: () => Temporal.PlainTime.from(zoned).toString({ smallestUnit: 'milliseconds' }), // 00:00:00.123
+
+    datetime: () => Temporal.PlainDateTime.from(zoned).toString({ smallestUnit: 'minutes' }), // 1960-04-27T00:00
+    'datetime second': () => Temporal.PlainDateTime.from(zoned), // 1960-04-27T00:00:00
+    'datetime ms': () => Temporal.PlainDateTime.from(zoned).toString({ smallestUnit: 'milliseconds' }), // 1960-04-27T00:00:00.123
+
+    'datetime utc': () => instant.toString({ smallestUnit: 'minute' }), // 1960-04-26T23:00Z
+    'datetime second utc': () => instant, // 1960-04-26T23:00:00Z
+    'datetime ms utc': () => instant.toString({ fractionalSecondDigits: 3 }), // 1960-04-26T23:00:00.000Z
+
+    'time utc': () =>
+      instant.toString({ smallestUnit: 'minute' }).substr(11, 6), // 23:00Z
+    'second utc': () => instant.toString().substr(11, 9), // 23:00:00Z
+    'ms utc': () =>
+      instant.toString({ fractionalSecondDigits: 3 }).substr(11, 13), // 23:00:00.000Z
+  }
+
+  return (temporalFormat[precision] || temporalFormat.day)().toString().replace('T', config.separator)
+}
+
+/**
+ * Supported precision keywords.
+ *
+ * @typedef { 'day' | 'year' | 'yearless' | 'month' | 'week' |
+ *            'time' | 'second' | 'ms' |
+ *            'time utc' | 'second utc' | 'ms utc' |
+ *            'datetime' | 'datetime second' | 'datetime ms' |
+ *            'datetime utc' | 'datetime second utc' | 'datetime ms utc' } Precision
+ */

src/temporal/index.js

@@ -1 +1,2 @@
 export { duration } from './duration.js'
+export { datetime } from './datetime.js'

tests/temporal/index.test.js

@@ -2,15 +2,14 @@ import { describe, expect, test } from 'vitest'
 
 import {
   DateTime,
-  datetime,
   utc,
   datetimeTz,
   tzOffset,
   setTimeSeparator,
   setTzSeparator,
 } from '../../src'
 
-import { duration } from '../../src/temporal'
+import { duration, datetime } from '../../src/temporal'
 import { daysBetween, weekNumber } from '../../src/temporal/utils/date'
 
 /**
@@ -37,7 +36,7 @@ const year10k = new Date(10000, 0, 1)
 
 const tzOffsetInMinutes = (new Date()).getTimezoneOffset() * -1
 
-describe.todo('datetime', () => {
+describe('datetime', () => {
   test('is a function', () => expect(datetime).toBeInstanceOf(Function))
   test('wrong type', () => expect(() => datetime(123)).toThrow(TypeError))