Fixing incorrect message timing display when changing timezones

src/libs/DateUtils.js

@@ -4,11 +4,10 @@ import {es, enGB} from 'date-fns/locale';
 import {
     formatDistanceToNow,
     subMinutes,
+    addDays,
+    subDays,
     isBefore,
     subMilliseconds,
-    isToday,
-    isTomorrow,
-    isYesterday,
     startOfWeek,
     endOfWeek,
     format,
@@ -85,6 +84,47 @@ function getLocalDateFromDatetime(locale, datetime, currentSelectedTimezone = ti
     return utcToZonedTime(parsedDatetime, currentSelectedTimezone);
 }
 
+/**
+ * Checks if a given date is today in the specified time zone.
+ *
+ * @param {Date} date - The date to compare.
+ * @param {String} timeZone - The time zone to consider.
+ * @returns {Boolean} True if the date is today; otherwise, false.
+ */
+function isToday(date, timeZone) {
+    const currentDate = new Date();
+    const currentDateInTimeZone = utcToZonedTime(currentDate, timeZone);
+    return isSameDay(date, currentDateInTimeZone);
+}
+
+/**
+ * Checks if a given date is tomorrow in the specified time zone.
+ *
+ * @param {Date} date - The date to compare.
+ * @param {String} timeZone - The time zone to consider.
+ * @returns {Boolean} True if the date is tomorrow; otherwise, false.
+ */
+function isTomorrow(date, timeZone) {
+    const currentDate = new Date();
+    const tomorrow = addDays(currentDate, 1); // Get the date for tomorrow in the current time zone
+    const tomorrowInTimeZone = utcToZonedTime(tomorrow, timeZone);
+    return isSameDay(date, tomorrowInTimeZone);
+}
+
+/**
+ * Checks if a given date is yesterday in the specified time zone.
+ *
+ * @param {Date} date - The date to compare.
+ * @param {String} timeZone - The time zone to consider.
+ * @returns {Boolean} True if the date is yesterday; otherwise, false.
+ */
+function isYesterday(date, timeZone) {
+    const currentDate = new Date();
+    const yesterday = subDays(currentDate, 1); // Get the date for yesterday in the current time zone
+    const yesterdayInTimeZone = utcToZonedTime(yesterday, timeZone);
+    return isSameDay(date, yesterdayInTimeZone);
+}
+
 /**
  * Formats an ISO-formatted datetime string to local date and time string
  *
@@ -117,13 +157,13 @@ function datetimeToCalendarTime(locale, datetime, includeTimeZone = false, curre
         yesterdayAt = yesterdayAt.toLowerCase();
     }
 
-    if (isToday(date)) {
+    if (isToday(date, currentSelectedTimezone)) {
         return `${todayAt} ${format(date, CONST.DATE.LOCAL_TIME_FORMAT)}${tz}`;
     }
-    if (isTomorrow(date)) {
+    if (isTomorrow(date, currentSelectedTimezone)) {
         return `${tomorrowAt} ${format(date, CONST.DATE.LOCAL_TIME_FORMAT)}${tz}`;
     }
-    if (isYesterday(date)) {
+    if (isYesterday(date, currentSelectedTimezone)) {
         return `${yesterdayAt} ${format(date, CONST.DATE.LOCAL_TIME_FORMAT)}${tz}`;
     }
     if (date >= startOfCurrentWeek && date <= endOfCurrentWeek) {
@@ -344,6 +384,9 @@ const DateUtils = {
     subtractMillisecondsFromDateTime,
     getDateStringFromISOTimestamp,
     getStatusUntilDate,
+    isToday,
+    isTomorrow,
+    isYesterday,
 };
 
 export default DateUtils;

tests/unit/DateUtilsTest.js

@@ -1,5 +1,5 @@
 import Onyx from 'react-native-onyx';
-import {format as tzFormat} from 'date-fns-tz';
+import {format as tzFormat, utcToZonedTime} from 'date-fns-tz';
 import {addMinutes, subHours, subMinutes, subSeconds, format, setMinutes, setHours, subDays, addDays} from 'date-fns';
 import CONST from '../../src/CONST';
 import DateUtils from '../../src/libs/DateUtils';
@@ -130,6 +130,34 @@ describe('DateUtils', () => {
         expect(result).toBe(expectedDateTime);
     });
 
+    describe('Date Comparison Functions', () => {
+        const today = new Date();
+        const tomorrow = addDays(today, 1);
+        const yesterday = subDays(today, 1);
+
+        const todayInTimezone = utcToZonedTime(today, timezone);
+        const tomorrowInTimezone = utcToZonedTime(tomorrow, timezone);
+        const yesterdayInTimezone = utcToZonedTime(yesterday, timezone);
+
+        it('isToday should correctly identify today', () => {
+            expect(DateUtils.isToday(todayInTimezone, timezone)).toBe(true);
+            expect(DateUtils.isToday(tomorrowInTimezone, timezone)).toBe(false);
+            expect(DateUtils.isToday(yesterdayInTimezone, timezone)).toBe(false);
+        });
+
+        it('isTomorrow should correctly identify tomorrow', () => {
+            expect(DateUtils.isTomorrow(tomorrowInTimezone, timezone)).toBe(true);
+            expect(DateUtils.isTomorrow(todayInTimezone, timezone)).toBe(false);
+            expect(DateUtils.isTomorrow(yesterdayInTimezone, timezone)).toBe(false);
+        });
+
+        it('isYesterday should correctly identify yesterday', () => {
+            expect(DateUtils.isYesterday(yesterdayInTimezone, timezone)).toBe(true);
+            expect(DateUtils.isYesterday(todayInTimezone, timezone)).toBe(false);
+            expect(DateUtils.isYesterday(tomorrowInTimezone, timezone)).toBe(false);
+        });
+    });
+
     describe('getDBTime', () => {
         it('should return the date in the format expected by the database', () => {
             const getDBTime = DateUtils.getDBTime();