feat: replace Date constructor with parseISO for improved date handling across calendar components #25

lib/calendar-alerts.ts

@@ -1,3 +1,4 @@
+import { parseISO } from 'date-fns';
 import type {
   CalendarEvent,
   CalendarEventAlert,
@@ -53,7 +54,7 @@ export function computeFireTime(
       baseTime = new Date(event.utcEnd).getTime();
     } else {
       // Compute end from start + duration
-      const startMs = new Date(event.start).getTime();
+      const startMs = parseISO(event.start).getTime();
       if (Number.isNaN(startMs)) return null;
       const durationMin = parseDuration(event.duration);
       baseTime = startMs + durationMin * 60000;
@@ -61,7 +62,7 @@ export function computeFireTime(
   } else {
     baseTime = event.utcStart
       ? new Date(event.utcStart).getTime()
-      : new Date(event.start).getTime();
+      : parseISO(event.start).getTime();
   }
 
   if (Number.isNaN(baseTime)) return null;

lib/calendar-invitation.ts

@@ -1,3 +1,4 @@
+import { parseISO } from 'date-fns';
 import type { Email, Attachment, CalendarEvent, CalendarParticipant, EmailBodyPart } from '@/lib/jmap/types';
 
 export type InvitationMethod =
@@ -534,7 +535,7 @@ function addDurationToDate(start: string, duration: string, _timeZone?: string |
   const minutes = parseInt(match[4] || '0');
   const seconds = parseInt(match[5] || '0');
 
-  const date = new Date(start);
+  const date = parseISO(start);
   if (isNaN(date.getTime())) return null;
 
   const isUTC = start.endsWith('Z') || start.includes('+');

lib/calendar-utils.ts

@@ -12,14 +12,14 @@ export interface CalendarWeekSegment {
 }
 
 export function getEventEndDate(event: CalendarEvent): Date {
-  const start = new Date(event.start);
+  const start = parseISO(event.start);
   if (!event.duration) return start;
   return new Date(start.getTime() + parseDuration(event.duration) * 60000);
 }
 
 export function getEventDisplayEndDate(event: CalendarEvent): Date {
   const end = getEventEndDate(event);
-  if (!event.showWithoutTime || end.getTime() <= new Date(event.start).getTime()) {
+  if (!event.showWithoutTime || end.getTime() <= parseISO(event.start).getTime()) {
     return end;
   }
   return subMilliseconds(end, 1);
@@ -27,7 +27,7 @@ export function getEventDisplayEndDate(event: CalendarEvent): Date {
 
 export function getEventDayBounds(event: CalendarEvent): { startDay: Date; endDay: Date } {
   return {
-    startDay: startOfDay(new Date(event.start)),
+    startDay: startOfDay(parseISO(event.start)),
     endDay: startOfDay(getEventDisplayEndDate(event)),
   };
 }
@@ -77,7 +77,7 @@ export function buildWeekSegments(events: CalendarEvent[], weekDays: Date[]): Ca
     if (left.event.showWithoutTime !== right.event.showWithoutTime) {
       return left.event.showWithoutTime ? -1 : 1;
     }
-    const timeDiff = new Date(left.event.start).getTime() - new Date(right.event.start).getTime();
+    const timeDiff = parseISO(left.event.start).getTime() - parseISO(right.event.start).getTime();
     if (timeDiff !== 0) return timeDiff;
     return (left.event.title || "").localeCompare(right.event.title || "");
   });
@@ -100,7 +100,7 @@ export function layoutOverlappingEvents(
   events: CalendarEvent[],
 ): { event: CalendarEvent; column: number; totalColumns: number }[] {
   const sorted = [...events].sort((a, b) => {
-    const diff = new Date(a.start).getTime() - new Date(b.start).getTime();
+    const diff = parseISO(a.start).getTime() - parseISO(b.start).getTime();
     if (diff !== 0) return diff;
     return parseDuration(b.duration) - parseDuration(a.duration);
   });