Fix length-of-day Julian/Gregorian transition issue (#51)

* Fix odd Julian/Gregorian calendar transition length-of-day bug.
* Increased test coverage for format-parse.ts.
* Documentation tweaks.

Author: kshetline

CHANGELOG.md

@@ -1,13 +1,18 @@
 _Updates limited to IANA tzdb updates omitted._
 
+### 3.10.2
+
+* Fixed a very edge-case bug where `getSecondsInDay()` and `getMinutesInDay()` might return 0 for the very last Julian calendar date before a transition to the Gregorian calendar.
+* Increased test coverage.
+
 ### 3.10.1
 
 * Minor documentation update.
 
 ### 3.10.0
 
 * Fixed bug with creating `DateTime` instances using `Date` objects.
-* Other minor edge-case bug fixes.
+* Other minor bug fixes.
 * Code coverage increased to 95%.
 * Updated build, linting, and documentation.
 * Improved sourcemaps.

README.md

@@ -12,7 +12,7 @@ Not all days are 24 hours. Some are 23 hours, or 25, or even 23.5 or 24.5 or 47
 * Supports and recognizes negative Daylight Saving Time.
 * Extensive date/time manipulation and calculation capabilities.
 * Many features available using a familiar Moment.js-style API.
-* Astronomical time conversions among TDT (Terrestrial Dynamic Time), UT1, UTC and TAI.
+* Astronomical time conversions among TDT (Terrestrial Dynamic Time), UT1, UTC, and TAI.
 * Local mean time, by geographic longitude, to one minute (of time) resolution.
 * Astronomical time conversions among TDT (Terrestrial Dynamic Time), UT1, UTC and TAI, as well as local mean time, by geographic longitude, to one minute (of time) resolution.
 * Internationalization via JavaScript’s `Intl` Internationalization API, with additional built-in i18n support for issues not covered by `Intl`, and US-English fallback for environments without `Intl` support.
@@ -979,7 +979,7 @@ The `epochMillis` getter/setter returns, or allows you to modify, the fundamenta
 
 For a TAI instance, `epochMillis` is the same as `taiMillis`, with `utcMillis` providing a conversion to or from UTC (or UT1 outside the well-defined UTC range). For a non-TAI instance `epochMillis` is the same as `utcMillis`, with `taiMillis` performing conversions.
 
-During a leap second the `epochMillis`/`utcMillis` value is pinned 59 seconds, 999 milliseconds into the minute in which the leap seconds occurs. The `taiMillis` value, however, still varies over the course of that second.
+During a leap second the `epochMillis`/`utcMillis` value is pinned 59 seconds, 999 milliseconds into the minute in which the leap second occurs. The `taiMillis` value, however, still varies over the course of that second.
 
 In the unlikely event a negative leap second is ever declared, the `epochMillis`/`utcMillis` value for a non-TAI `DateTime` instance will simply skip over the leap second, while `taiMillis` advances contiguously.
 
@@ -1031,7 +1031,7 @@ All arguments to the constructor are optional. When passed no arguments, `new Da
 
 * `initialTime`: This can be a single number (for milliseconds since 1970-01-01T00:00 UTC), an ISO-8601 date as a string, and ECMA-262 date as string, an ASP.​NET JSON date string, a JavaScript `Date` object, [a `DateAndTime` object](#the-ymddate-and-dateandtime-objects), an array of numbers (in the order year, month, day, hour, etc.), or a `null`, which causes the current time to be used.
 * `timezone`: This can be a `Timezone` instance, a string specifying an IANA timezone (e.g. 'Pacific/Honolulu'), a UTC offset (e.g. 'UTC+04:00'), or `null` to use the default timezone.
-* `locale`: a locale string (e.g. 'fr-FR'), an array of locales strings in order of preference (e.g. ['fr-FR', 'fr-CA', 'en-US']), or `null` to use the default locale.
+* `locale`: a locale string (e.g. 'fr-FR'), an array of locale strings in order of preference (e.g. ['fr-FR', 'fr-CA', 'en-US']), or `null` to use the default locale.
 * `gregorianChange`: The first date when the Gregorian calendar is active, the string `'J'` for a pure Julian calendar, the string 'G' for a pure Gregorian calendar, the constant `ttime.PURE_JULIAN`, the constant `ttime.PURE_GREGORIAN`, or `null` for the default of 1582-10-15. A date can take the form of a year-month-day ISO-8601 date string (e.g. '1752-09-14'), a year-month-day numeric array (e.g. [1918, 2, 14]), or a date as a `YMDDate` object.
 
 As a string, `initialTime` can also include a trailing timezone or UTC offset, using the letter `Z` to indicate UTC (e.g. '1969‑07‑12T20:17Z'), or a specific timezone (e.g. '1969‑07‑20T16:17 EDT', '1969‑07‑20T16:17 America/New_York', or '1969‑07‑20T16:17-0400').

package-lock.json

@@ -1,6 +1,6 @@
 {
   "name": "@tubular/time",
-  "version": "3.10.1",
+  "version": "3.10.2",
   "description": "Date/time, IANA timezones, leap seconds, TAI/UTC conversions, calendar with settable Julian/Gregorian switchover",
   "module": "dist/index.min.mjs",
   "main": "dist/index.min.cjs",

package.json

@@ -709,7 +709,7 @@ export class Calendar {
     if (j < 0) {
       if (year === this.lastJulianYear && month === this.lastJulianMonth) {
         if (day > this.lastJulianDate)
-          day = this.lastJulianDate;
+          day = this.lastJulianDate + 1;
       }
       else if (year === this.gcYear && month === this.gcMonth && (day > this.lastJulianDate ||
                (this.lastJulianMonth !== this.gcMonth && this.lastJulianMonth > 0)) && day < this.gcDate) {

src/calendar.ts

@@ -76,13 +76,16 @@ describe('DateTime', () => {
     expect(new DateTime('2021-11-07T01:23').compare(new DateTime('2021-11-07T01:23', Timezone.guess()))).to.equal(0);
     DateTime.setDefaultTimezone(saveZone);
 
-    const dt = new DateTime();
+    let dt = new DateTime();
 
     dt.locale = 'fr';
     expect(dt.locale).to.equal('fr');
 
     dt.locale = undefined;
     expect(() => dt.format('D')).not.to.throw;
+
+    dt = new DateTime('2025-06-20T12:00', 'America/Chicago', [2025, 7, 4]);
+    expect(dt.getSecondsInDay()).to.equal(86400);
   });
 
   it('should properly determine locale-specific starting days of the week', () => {

src/date-time.spec.ts

@@ -1,6 +1,6 @@
 import { expect } from 'chai';
 import { DateTime } from './date-time';
-import ttime, { initTimezoneLarge } from './index';
+import ttime, { initTimezoneLarge, Timezone } from './index';
 import { localeList } from './locale-data';
 import { analyzeFormat, parse } from './format-parse';
 
@@ -17,6 +17,9 @@ describe('FormatParse', () => {
     expect(new DateTime('2022-07-07 8:08 PST').format('IMM{hourCycle:h23} zzz ZZZ z')).to.equal('Jul 7, 2022, 09:08:00 Pacific Daylight Time America/Los_Angeles PDT');
     expect(new DateTime('2022-07-07 8:08 PDT').format('IMM zzz ZZZ z')).to.equal('Jul 7, 2022, 8:08:00 AM Pacific Daylight Time America/Los_Angeles PDT');
     expect(new DateTime('1995-05-06 EDT').format('IMM zzz ZZZ z')).to.equal('May 6, 1995, 12:00:00 AM Eastern Daylight Time America/New_York EDT');
+    expect(new DateTime('1995-05-06 TAI').format('IS', 'en-us')).to.equal('5/6/95');
+    expect(new DateTime('1995-05-06T21:00', 'UTC+0100').format('ISS', 'en-us')).to.equal('5/6/95, 9:00 PM');
+    expect(new DateTime('1995-05-06T21:00', 'UTC+0115').format('ISS', 'en-us')).to.equal('5/6/95, 9:00\u202FPM');
     expect(new DateTime('foo').valid).is.false;
     expect(new DateTime('foo').wallTime.error).to.equal('Invalid ISO date/time');
     expect(new DateTime('2021-01-02').format('GGGG-[W]WW-E')).to.equal('2020-W53-6');
@@ -93,6 +96,8 @@ describe('FormatParse', () => {
     expect(parse('11/7/2021 1:25₂ AM', 'MM/DD/YYYY h:m a', 'America/Denver').toString()).to.equal('DateTime<2021-11-07T01:25:00.000₂-07:00>');
     expect(parse('2016-12-31T23:59:60', ttime.DATETIME_LOCAL_SECONDS, 'UTC',
       undefined, true).toString()).to.equal('DateTime<2016-12-31T23:59:60.000 +00:00>');
+    expect(() => parse('1/17/2022 1:22:33', 'MM/Do/YYYY H:m:s', 'UTC')).to.throw();
+    expect(() => parse('1/17/2022 1:22:33', 'MM/d/YYYY H:m:s', 'UTC')).to.throw();
   });
 
   it('should correctly handle two-digit years', () => {
@@ -168,6 +173,8 @@ describe('FormatParse', () => {
   it('should be able to parse times with timezones', () => {
     expect(parse('Jul 7, 2022 04:05 PM America/Chicago', 'MMM D, y n hh:mm A z').epochMillis)
       .to.equal(Date.UTC(2022, 6, 7, 16, 5, 0) + 5 * 3_600_000);
+    expect(parse('Jul 7, 2022 04:05 PM America/Chicago', 'MMM D, y n hh:mm A Z').epochMillis)
+      .to.equal(Date.UTC(2022, 6, 7, 16, 5, 0) + 5 * 3_600_000);
     expect(parse('Jul 7, 2022 04:05 PM EDT', 'MMM D, y n hh:mm A z').epochMillis)
       .to.equal(Date.UTC(2022, 6, 7, 16, 5, 0) + 4 * 3_600_000);
     expect(parse('Jul 7, 2022 04:05 PM PST', 'MMM D, y n hh:mm A z').epochMillis)
@@ -210,4 +217,24 @@ describe('FormatParse', () => {
     expect(new DateTime('2021-08-20T20:36').format('MMM D, y n hh:mm~ A z', 'en')).to.equal('Aug 20, 2021 08:36~ PM EDT');
     expect(parse('1/17/2022 1:22:33', 'MM~/DD~/YYYY~ H:m:s', 'UTC').toIsoString(19)).to.equal('2022-01-17T01:22:33');
   });
+
+  it('should handling special formatting', () => {
+    expect(new DateTime('2021-08').format('YYYYYY')).to.equal('+002021');
+    expect(new DateTime('-2021-08').format('YYYYYY')).to.equal('-002021');
+    expect(new DateTime('2021-08-08').format('GGGG gggg GG gg')).to.equal('2021 2021 21 21');
+    expect(new DateTime('-2021-08-08').format('GGGG gggg GG gg')).to.equal('-2021 -2021 -21 -21');
+    expect(new DateTime('22021-08-08').format('GGGG gggg GG gg')).to.equal('+22021 +22021 21 21');
+    expect(new DateTime('-22021-08-08').format('GGGG gggg GG gg')).to.equal('-22021 -22021 -21 -21');
+    expect(new DateTime('2021-08-08').format('W w D~')).to.equal('31 33 8');
+    expect(new DateTime('2021-08-08T12:03:04', Timezone.OS_ZONE).format('ZZZ')).to.match(/\w/);
+    expect(new DateTime('2021-08-08T12:03:04 TAI').format('zzz')).to.equal('Temps Atomique International');
+    expect(new DateTime('2025-07-03').format('(d) dd MMM Do, YYYY')).to.equal('(4) Th Jul 3rd, 2025');
+    expect(new DateTime('1970-01-01T12:03:04Z').format('XX xx XT xt X x KK K kk k m s zz ZZ V'))
+      .to.equal('43384 43384000 43392 43392 43384 43384000 00 0 12 12 3 4 UTC +0000  ');
+    expect(new DateTime('1970-01-01T12:03:04.77Z').format('mm:ss.SSS')).to.equal('03:04.770');
+    expect(new DateTime('1970-01-01T12:03:04 EST').format('LLL zz', 'en-us'))
+      .to.equal('January 1, 1970 at 12:03 PM EST');
+    expect(parse('11/7/2021 1:25 AM', 'MM/DD/YYYY h:m a', 'America/Denver').format('r')).to.equal('');
+    expect(new DateTime('foo').format('YYYYYY')).to.equal('##Invalid_Date##');
+  });
 });

src/format-parse.spec.ts

@@ -18,7 +18,7 @@ const shortOpts = { Y: 'year', M: 'month', D: 'day', w: 'weekday', h: 'hour', m:
                     ds: 'dateStyle', ts: 'timeStyle', e: 'era' };
 const shortOptValues = { f: 'full', m: 'medium', n: 'narrow', s: 'short', l: 'long', dd: '2-digit', d: 'numeric' };
 const styleOptValues = { F: 'full', L: 'long', M: 'medium', S: 'short' };
-const patternTokens = /({[A-Za-z0-9/_]+?!?}|V|v|R|r|I[FLMSx][FLMS]?|MMMM~?|MMM~?|MM~?|Mo|M~?|Qo|Q|DDDD|DDD|Do|DD~?|D~?|dddd|ddd|do|dd|d|E|e|ww|wo|w|WW|Wo|W|YYYYYY|yyyyyy|YYYY~?|yyyy|YY|yy|Y~?|y~?|N{1,5}|n|gggg|gg|GGGG|GG|A|a|HH|H|hh|h|kk|k|mm|m|ss|s|LTS|LT|LLLL|llll|LLL|lll|LL|ll|L|l|S+|ZZZ|zzz|ZZ|zz|Z|z|XT|xt|XX|xx|X|x)/g;
+const patternTokens = /({[A-Za-z0-9/_]+?!?}|V|v|R|r|I[FLMSx][FLMS]?|MMMM~?|MMM~?|MM~?|Mo|M~?|Qo|Q|DDDD|DDD|Do|DD~?|D~?|dddd|ddd|do|dd|d|E|e|ww|wo|w|WW|Wo|W|YYYYYY|yyyyyy|YYYY~?|yyyy|YY|yy|Y~?|y~?|N{1,5}|n|gggg|gg|GGGG|GG|A|a|HH|H|hh|h|KK|K|kk|k|mm|m|ss|s|LTS|LT|LLLL|llll|LLL|lll|LL|ll|L|l|S+|ZZZ|zzz|ZZ|zz|Z|z|XT|xt|XX|xx|X|x)/g;
 const cachedLocales: Record<string, ILocale> = {};
 const invalidZones = new Set<string>();
 const warnedZones = new Set<string>();
@@ -234,14 +234,15 @@ export function format(dt: DateTime, fmt: string, localeOverride?: string | stri
     return '##Invalid_Date##';
 
   const currentLocale = normalizeLocale(localeOverride ?? dt.locale);
-  const localeNames = !hasIntlDateTime ? 'en' : currentLocale;
+  const localeNames = !hasIntlDateTime ? /* istanbul ignore next: unreached sanity check */ 'en' : currentLocale;
   const locale = getLocaleInfo(localeNames);
   const cjk = /^(ja|ko|zh)/.test(locale.name);
   const ko = /^ko/.test(locale.name);
   const dateMarks = cjk ? ko ? ['년', '월', '일'] : ['年', '月', '日'] : ['\x80', '\x80', '\x80'];
   let usesDateMarks = false;
   const zeroAdj = locale.zeroDigit.charCodeAt(0) - 48;
   const toNum = (n: number | string, pad = 1): string => {
+    /* istanbul ignore next: unreached sanity check */
     if (n == null || (isNumber(n) && isNaN(n)))
       return '?'.repeat(pad);
     else
@@ -473,7 +474,7 @@ export function format(dt: DateTime, fmt: string, localeOverride?: string | stri
       case 'A': // AM/PM indicator (may have more than just two forms)
       case 'a':
         {
-          const values = locale.meridiemAlt ?? locale.meridiem;
+          const values = locale.meridiemAlt ?? /* istanbul ignore next: unreached sanity check */ locale.meridiem;
           const dayPartsForHour = values[values.length === 2 ? floor(hour / 12) : hour];
 
           // If there is no case distinction between the first two forms, use the first form
@@ -482,7 +483,7 @@ export function format(dt: DateTime, fmt: string, localeOverride?: string | stri
               (!isCased(dayPartsForHour[0]) && !isCased(dayPartsForHour[0])))
             result.push(dayPartsForHour[0]);
           else
-            result.push(dayPartsForHour[field === 'A' && dayPartsForHour.length > 1 ? 1 : 0]);
+            result.push(dayPartsForHour[field === 'A' && dayPartsForHour.length > 1 ? 1 : /* istanbul ignore next: unreached sanity check */ 0]);
         }
         break;
 
@@ -523,8 +524,10 @@ export function format(dt: DateTime, fmt: string, localeOverride?: string | stri
         {
           const localeFormat = locale.dateTimeFormats[field];
 
+          /* istanbul ignore next: unreached sanity check */
           if (localeFormat == null)
             result.push(`[${field}?]`);
+          /* istanbul ignore next: unreached sanity check */
           else if (isString(localeFormat))
             result.push(format(dt, localeFormat, localeOverride));
           else
@@ -558,14 +561,15 @@ export function format(dt: DateTime, fmt: string, localeOverride?: string | stri
           result.push(getDatePart(locale.dateTimeFormats.z, dt.epochMillis, 'timeZoneName'));
           break;
         }
-        else if (invalidZones.has(zoneName)) {
+        else /* istanbul ignore next: unreached sanity check */ if (invalidZones.has(zoneName)) {
           result.push(dt.timezone.getDisplayName(dt.epochMillis));
           break;
         }
         else if (zoneName !== 'OS') {
           result.push(zoneName);
           break;
         }
+        /* istanbul ignore else: unreached sanity check */
         else
           field = 'Z';
 
@@ -584,7 +588,7 @@ export function format(dt: DateTime, fmt: string, localeOverride?: string | stri
 
       case 'R':
       case 'r':
-        result.push(wt.occurrence === 2 ? '\u2082' : field === 'R' ? ' ' : ''); // Subscript 2
+        result.push(wt.occurrence === 2 ? '\u2082' : field === 'R' ? ' ' : ''); // Subscript 2 (₂)
         break;
 
       case 'n':
@@ -595,11 +599,13 @@ export function format(dt: DateTime, fmt: string, localeOverride?: string | stri
         break;
 
       default:
+        /* istanbul ignore else: unreached sanity check */
         if (field.startsWith('N'))
           result.push(locale.eras[(year < 1 ? 0 : 1) + (field.length === 4 ? 2 : 0)]);
         else if (field.startsWith('I')) {
+          /* istanbul ignore else: unreached backup for lack of Intl library */
           if (hasIntlDateTime) {
-            const formatKey = field + (dtfMods ? JSON.stringify(dtfMods) : '');
+            const formatKey = field + (dtfMods ? JSON.stringify(dtfMods) : /* istanbul ignore next: unreached sanity check */ '');
             let intlFormat = locale.dateTimeFormats[formatKey] as DateTimeFormat;
 
             if (!intlFormat) {
@@ -782,6 +788,7 @@ function getLocaleInfo(localeNames: string | string[]): ILocale {
 
   locale.name = isArray(localeNames) ? localeNames.join(',') : localeNames;
 
+  /* istanbul ignore else: unreached backup for lack of Intl library */
   if (hasIntlDateTime) {
     locale.months = [];
     locale.monthsShort = [];
@@ -858,6 +865,7 @@ function getLocaleInfo(localeNames: string | string[]): ILocale {
       if (fullValue && fullValue !== value) {
         newHourForm += ',' + fullValue;
 
+        /* istanbul ignore else: unreached sanity check */
         if (fullValue === lcFullValue)
           newMeridiems.push(fullValue);
         else
@@ -917,6 +925,7 @@ function generatePredefinedFormats(locale: ILocale, timezone: string): void {
   locale.cachedTimezone = timezone;
   locale.dateTimeFormats = {};
 
+  /* istanbul ignore else: unreached backup for lack of Intl library */
   if (hasIntlDateTime) {
     locale.dateTimeFormats.LLLL = fmt({ Y: 'd', M: 'l', D: 'd', w: 'l', h: 'd', m: 'dd' }); // Thursday, September 4, 1986 8:30 PM
     locale.dateTimeFormats.llll = fmt({ Y: 'd', M: 's', D: 'd', w: 's', h: 'd', m: 'dd' }); // Thu, Sep 4, 1986 8:30 PM
@@ -953,6 +962,7 @@ function generatePredefinedFormats(locale: ILocale, timezone: string): void {
 }
 
 function isLocale(locale: string | string[], matcher: string): boolean {
+  /* istanbul ignore else: unreached sanity check */
   if (isString(locale))
     return locale.startsWith(matcher);
   else if (locale.length > 0)