From e635dff5cf07578ef4ecb21557ef0a4eb2d73b5d Mon Sep 17 00:00:00 2001 From: Quantum Date: Sat, 12 Feb 2022 13:39:32 -0500 Subject: [PATCH] Implement Long Count date calculation --- src/dates.test.ts | 63 ++++++++++++++++++++++++++++++++++++++++++++++- src/dates.ts | 19 ++++++++++++++ 2 files changed, 81 insertions(+), 1 deletion(-) diff --git a/src/dates.test.ts b/src/dates.test.ts index d9d06a5..4e3c95c 100644 --- a/src/dates.test.ts +++ b/src/dates.test.ts @@ -1,4 +1,4 @@ -import {dateName, frJDN, gregorianJDN, jdnGregorian, monthName} from './dates'; +import {dateName, frJDN, gregorianJDN, jdnGregorian, jdnLongCount, monthName} from './dates'; describe('gregorianJDN', () => { it('works', () => { @@ -51,6 +51,67 @@ describe('jdnGregorian', () => { }); }); +describe('jdnLongCount', () => { + it('works for normal dates', () => { + expect(jdnLongCount(2456282)).toEqual('12.19.19.17.19'); + expect(jdnLongCount(2459413)).toEqual('13.0.8.12.10'); + expect(jdnLongCount(1708616)).toEqual('7.16.3.2.13'); + expect(jdnLongCount(1787816)).toEqual('8.7.3.2.13'); + expect(jdnLongCount(1709981)).toEqual('7.16.6.16.18'); + expect(jdnLongCount(1725275)).toEqual('7.18.9.7.12'); + expect(jdnLongCount(1727095)).toEqual('7.18.14.8.12'); + expect(jdnLongCount(1731775)).toEqual('7.19.7.8.12'); + expect(jdnLongCount(1734635)).toEqual('7.19.15.7.12'); + expect(jdnLongCount(1751618)).toEqual('8.2.2.10.15'); + expect(jdnLongCount(1758818)).toEqual('8.3.2.10.15'); + expect(jdnLongCount(1767234)).toEqual('8.4.5.17.11'); + expect(jdnLongCount(1773428)).toEqual('8.5.3.3.5'); + expect(jdnLongCount(1778230)).toEqual('8.5.16.9.7'); + expect(jdnLongCount(1780300)).toEqual('8.6.2.4.17'); + expect(jdnLongCount(2283483)).toEqual('11.16.0.0.0'); + expect(jdnLongCount(584283)).toEqual('0.0.0.0.0'); + expect(jdnLongCount(728283)).toEqual('1.0.0.0.0'); + expect(jdnLongCount(872283)).toEqual('2.0.0.0.0'); + expect(jdnLongCount(1016283)).toEqual('3.0.0.0.0'); + expect(jdnLongCount(1160283)).toEqual('4.0.0.0.0'); + expect(jdnLongCount(1304283)).toEqual('5.0.0.0.0'); + expect(jdnLongCount(1448283)).toEqual('6.0.0.0.0'); + expect(jdnLongCount(1592283)).toEqual('7.0.0.0.0'); + expect(jdnLongCount(1736283)).toEqual('8.0.0.0.0'); + expect(jdnLongCount(1880283)).toEqual('9.0.0.0.0'); + expect(jdnLongCount(2024283)).toEqual('10.0.0.0.0'); + expect(jdnLongCount(2168283)).toEqual('11.0.0.0.0'); + expect(jdnLongCount(2312283)).toEqual('12.0.0.0.0'); + expect(jdnLongCount(2456283)).toEqual('13.0.0.0.0'); + expect(jdnLongCount(2600283)).toEqual('14.0.0.0.0'); + expect(jdnLongCount(2744283)).toEqual('15.0.0.0.0'); + expect(jdnLongCount(2888283)).toEqual('16.0.0.0.0'); + expect(jdnLongCount(3032283)).toEqual('17.0.0.0.0'); + expect(jdnLongCount(3176283)).toEqual('18.0.0.0.0'); + expect(jdnLongCount(3320283)).toEqual('19.0.0.0.0'); + expect(jdnLongCount(3464283)).toEqual('1.0.0.0.0.0'); + expect(jdnLongCount(1941383)).toEqual('9.8.9.13.0'); + }); + + it('works for insane dates in the future', () => { + expect(jdnLongCount(591279564516)).toEqual('1.5.13.5.5.4.0.11.13.13'); + expect(jdnLongCount(570988471138)).toEqual('1.4.15.12.19.13.13.3.8.15'); + expect(jdnLongCount(166410754861)).toEqual('7.4.9.1.6.3.13.14.18'); + expect(jdnLongCount(176632006419)).toEqual('7.13.6.10.7.1.19.4.16'); + expect(jdnLongCount(652557304645)).toEqual('1.8.6.9.2.3.17.16.10.2'); + expect(jdnLongCount(140305417242)).toEqual('6.1.15.16.19.2.7.1.19'); + expect(jdnLongCount(805888002058)).toEqual('1.14.19.11.2.0.8.0.8.15'); + expect(jdnLongCount(176433890202)).toEqual('7.13.3.1.11.5.16.7.19'); + expect(jdnLongCount(331888546361)).toEqual('14.8.1.18.17.10.5.13.18'); + expect(jdnLongCount(657363764536)).toEqual('1.8.10.12.11.2.1.14.0.13'); + }); + + it('returns null for dates before inception of calendar', () => { + expect(jdnLongCount(0)).toBeNull(); + expect(jdnLongCount(584282)).toBeNull(); + }); +}) + describe('monthName', () => { it('works', () => { expect(monthName(1)).toBe('Vendémiaire'); diff --git a/src/dates.ts b/src/dates.ts index 14ac820..abb544f 100644 --- a/src/dates.ts +++ b/src/dates.ts @@ -96,6 +96,25 @@ export function jdnGregorian(jdn: number): Date { return new Date(year, month, day); } +export function jdnLongCount(jdn: number): string | null { + let z = jdn - 584283; + if (z < 0) + return null; + + const parts = [z % 20, Math.floor(z / 20) % 18]; + z = Math.floor(z / 360); + while (z > 0) { + parts.push(z % 20); + z = Math.floor(z / 20); + } + + while (parts.length < 5) { + parts.push(0); + } + + return parts.reverse().join('.'); +} + export function monthName(month: Month): string { return monthNames[month]; }