fix(chores): a display in another time zone shows the household's chore day

client/src/utils/choreHelpers.js

@@ -1,7 +1,12 @@
-import { CronExpressionParser } from 'cron-parser';
 import { getServerTimezoneSync } from './timezone.js';
-
-export function shouldShowChoreToday(schedule) {
+import { cronFiresOn } from './choreDays.js';
+
+// Whether a chore is on today's list. "Today" is the household's date (the
+// server's time zone), not the browser's: a display in another zone must
+// show the same chores as the server counts for the daily bonus. The
+// crontab is matched on that date's calendar fields, as the server's
+// cronFiresOnDate and the history row's cronFiresOn do.
+export function shouldShowChoreToday(schedule, today = getTodayDateString()) {
   if (!schedule.visible) {
     return false;
   }
@@ -16,24 +21,7 @@ export function shouldShowChoreToday(schedule) {
     return true;
   }
 
-  try {
-    const tz = getServerTimezoneSync();
-    const today = new Date();
-    today.setHours(0, 0, 0, 0);
-
-    const interval = CronExpressionParser.parse(schedule.crontab, {
-      currentDate: new Date(today.getTime() + 24 * 60 * 60 * 1000),
-      tz
-    });
-
-    const prevOccurrence = interval.prev().toDate();
-    prevOccurrence.setHours(0, 0, 0, 0);
-
-    return prevOccurrence.getTime() === today.getTime();
-  } catch (error) {
-    console.error('Error parsing crontab:', schedule.crontab, error);
-    return false;
-  }
+  return cronFiresOn(schedule.crontab, today);
 }
 
 /**
@@ -61,7 +49,7 @@ export function hasOutstandingBonusChore(schedules, history, userId, today) {
   return schedules
     .filter((schedule) => schedule.user_id === userId
       && (schedule.clam_value || 0) > 0
-      && shouldShowChoreToday(schedule))
+      && shouldShowChoreToday(schedule, today))
     .some((schedule) => !history.some((entry) => entry.chore_schedule_id === schedule.id
       && entry.user_id === userId
       && entry.date === today));

client/src/utils/choreHelpers.test.js

@@ -1,7 +1,8 @@
-import { describe, it, expect, vi, beforeAll, afterAll } from 'vitest';
+import { describe, it, expect, vi, beforeAll, afterAll, afterEach } from 'vitest';
 
+const zones = vi.hoisted(() => ({ server: 'UTC' }));
 vi.mock('./timezone.js', () => ({
-    getServerTimezoneSync: () => 'UTC',
+    getServerTimezoneSync: () => zones.server,
 }));
 
 import { shouldShowChoreToday, convertDaysToCrontab, getDueDateStatus, formatDueDate, hasOutstandingBonusChore, compareByKey, countsTowardDailyBonus } from './choreHelpers.js';
@@ -151,11 +152,6 @@ describe('hasOutstandingBonusChore', () => {
 
     it('does not block on a bonus chore that is not due today', () => {
         // Thursday-only chore, uncompleted, on a Sunday: nothing is outstanding.
-        // Avoid the day immediately after TODAY here: shouldShowChoreToday
-        // compares a cron occurrence resolved in the SERVER zone against local
-        // midnight, so with the mocked server zone (UTC) ahead of the runner's,
-        // tomorrow-00:00 lands on today's local date. That skew is issue #21,
-        // not this helper.
         const schedules = [bonus(24, '0 0 * * 4')];
         expect(hasOutstandingBonusChore(schedules, [], 4, TODAY)).toBe(false);
     });
@@ -305,3 +301,48 @@ describe('compareByKey', () => {
         ], byNext)).toEqual(['three', 'seven']);
     });
 });
+
+// A display whose browser is in another time zone than the household still
+// shows the household's day: the server counts chores, and the daily bonus,
+// on that date (fork issue #68).
+describe('shouldShowChoreToday across time zones', () => {
+    const browserTz = process.env.TZ;
+    const MONDAY_ONLY = { visible: true, crontab: '0 0 * * 1' };
+
+    afterEach(() => {
+        vi.useRealTimers();
+        zones.server = 'UTC';
+        if (browserTz === undefined) delete process.env.TZ; else process.env.TZ = browserTz;
+    });
+
+    const at = (iso, browser, server) => {
+        process.env.TZ = browser;
+        zones.server = server;
+        vi.useFakeTimers();
+        vi.setSystemTime(new Date(iso));
+    };
+
+    it('a browser west of the household follows the household into Monday', () => {
+        // Monday 03:00 in UTC is still Sunday evening in Los Angeles.
+        at('2026-10-19T03:00:00Z', 'America/Los_Angeles', 'UTC');
+        expect(shouldShowChoreToday(MONDAY_ONLY)).toBe(true);
+    });
+
+    it('a browser west of the household does not show Monday chores on Sunday', () => {
+        // Sunday 20:00 in UTC; Los Angeles is Sunday too, the household is Sunday.
+        at('2026-10-18T20:00:00Z', 'America/Los_Angeles', 'UTC');
+        expect(shouldShowChoreToday(MONDAY_ONLY)).toBe(false);
+    });
+
+    it('a browser behind a household in Tokyo follows Tokyo', () => {
+        // Sunday 16:00 UTC is Monday 01:00 in Tokyo.
+        at('2026-10-18T16:00:00Z', 'UTC', 'Asia/Tokyo');
+        expect(shouldShowChoreToday(MONDAY_ONLY)).toBe(true);
+    });
+
+    it('a browser east of the household waits for the household day', () => {
+        // Monday 01:00 in Tokyo is Sunday 16:00 in UTC, the household's zone.
+        at('2026-10-18T16:00:00Z', 'Asia/Tokyo', 'UTC');
+        expect(shouldShowChoreToday(MONDAY_ONLY)).toBe(false);
+    });
+});

client/src/utils/interfaceSettings.js

@@ -1,4 +1,5 @@
 import { normalizeDockHideMinutes } from './dockIdleHide.js';
+import { getTodayDateString } from './choreHelpers.js';
 import {
   DEFAULT_EXPAND_IDLE_MINUTES,
   DEFAULT_EXPAND_METHOD,
@@ -201,14 +202,12 @@ export const normalizeVacationModeSettings = (raw) => ({
 // mirrors the server's isVacationActiveOn, and gives bounded vacations
 // client-side auto-expiry — chimes and the vacation screensaver come back on
 // their own the day after endDate.
-export const isVacationModeActiveToday = (settings, today = null) => {
+// Vacation dates are the household's, so "today" is the household's date
+// (the server's time zone), not the browser's.
+export const isVacationModeActiveToday = (settings, today = getTodayDateString()) => {
   if (!settings || settings.enabled !== true) return false;
-  const d = today || (() => {
-    const now = new Date();
-    return `${now.getFullYear()}-${String(now.getMonth() + 1).padStart(2, '0')}-${String(now.getDate()).padStart(2, '0')}`;
-  })();
-  if (settings.startDate && d < settings.startDate) return false;
-  if (settings.endDate && d > settings.endDate) return false;
+  if (settings.startDate && today < settings.startDate) return false;
+  if (settings.endDate && today > settings.endDate) return false;
   return true;
 };
 

client/src/utils/interfaceSettings.test.js

@@ -1,4 +1,10 @@
-import { describe, it, expect, beforeEach, vi } from 'vitest';
+import { describe, it, expect, beforeEach, afterEach, vi } from 'vitest';
+
+const zones = vi.hoisted(() => ({ server: 'UTC' }));
+vi.mock('./timezone.js', async (importOriginal) => ({
+    ...(await importOriginal()),
+    getServerTimezoneSync: () => zones.server,
+}));
 
 // The vitest environment is node — provide a minimal localStorage.
 const storageBacking = new Map();
@@ -107,6 +113,28 @@ describe('isVacationModeActiveToday', () => {
     });
 });
 
+// With no date passed (as app.jsx calls it), "today" is the household's date,
+// not the browser's (fork issue #68).
+describe('isVacationModeActiveToday without a date', () => {
+    const browserTz = process.env.TZ;
+    afterEach(() => {
+        vi.useRealTimers();
+        zones.server = 'UTC';
+        if (browserTz === undefined) delete process.env.TZ; else process.env.TZ = browserTz;
+    });
+
+    it('starts on the household date when the browser is still on the day before', () => {
+        // 03:00 UTC on the 20th is the evening of the 19th in Los Angeles.
+        process.env.TZ = 'America/Los_Angeles';
+        vi.useFakeTimers();
+        vi.setSystemTime(new Date('2026-07-20T03:00:00Z'));
+        const range = { enabled: true, startDate: '2026-07-20', endDate: '2026-07-25' };
+        expect(isVacationModeActiveToday(range)).toBe(true);
+        zones.server = 'America/Los_Angeles';
+        expect(isVacationModeActiveToday(range)).toBe(false);
+    });
+});
+
 import { hexToRgbTriplet, applyInterfaceColors } from './interfaceSettings.js';
 
 describe('hexToRgbTriplet', () => {

client/src/utils/timezone.js

@@ -1,6 +1,8 @@
 import { API_BASE_URL } from './apiConfig.js';
 
-const FALLBACK_TIMEZONE = 'America/New_York';
+// Until /api/timezone answers (or if it fails), the browser's own zone is the
+// best guess; watchServerTimezone corrects it on its next check.
+const FALLBACK_TIMEZONE = Intl.DateTimeFormat().resolvedOptions().timeZone || 'UTC';
 
 let cachedTimezone = null;
 

client/src/utils/timezone.test.js

@@ -1,5 +1,7 @@
 import { describe, it, expect, beforeEach, afterEach, vi } from 'vitest';
 
+const BROWSER_TZ = Intl.DateTimeFormat().resolvedOptions().timeZone;
+
 describe('timezone utilities', () => {
     const originalFetch = globalThis.fetch;
 
@@ -28,21 +30,21 @@ describe('timezone utilities', () => {
         expect(fetchMock).toHaveBeenCalledTimes(1);
     });
 
-    it('falls back to America/New_York when fetch fails', async () => {
+    it('falls back to the browser\'s own zone when fetch fails', async () => {
         globalThis.fetch = vi.fn(async () => {
             throw new Error('network down');
         });
 
         const timezone = await import('./timezone.js');
         const value = await timezone.getServerTimezone();
 
-        expect(value).toBe('America/New_York');
+        expect(value).toBe(BROWSER_TZ);
     });
 
     it('getServerTimezoneSync defaults before initialization', async () => {
         const timezone = await import('./timezone.js');
 
-        expect(timezone.getServerTimezoneSync()).toBe('America/New_York');
+        expect(timezone.getServerTimezoneSync()).toBe(BROWSER_TZ);
     });
 
     it('initTimezone primes the cache', async () => {
@@ -81,7 +83,7 @@ describe('timezone utilities', () => {
 
         const timezone = await import('./timezone.js');
         await expect(timezone.saveServerTimezone('Nope')).rejects.toThrow('Unknown time zone: Nope');
-        expect(timezone.getServerTimezoneSync()).toBe('America/New_York');
+        expect(timezone.getServerTimezoneSync()).toBe(BROWSER_TZ);
     });
 
     describe('watchServerTimezone', () => {