endDate is exclusive for allday events

helpers/date.ts

@@ -80,3 +80,7 @@ export function nowInTz(timezone = 'Europe/Berlin'): Date {
   const now = new Date()
   return utcToZonedTime(now, timezone)
 }
+
+export function getNextDay(date: Date) {
+  return addDays(date, 1)
+}

lib/googlecalendar.ts

@@ -1,7 +1,7 @@
 import { google } from 'googleapis'
 import { getBaseURL } from '../helpers/url'
 import { Booking } from '../db/booking'
-import { getDays } from '../helpers/date'
+import { getDays, getNextDay, dateFormatBackend } from '../helpers/date'
 import { log } from '../helpers/log'
 
 const calendarId = process.env.GOOGLE_CALENDAR_ID
@@ -66,18 +66,19 @@ function getDescription(booking: Booking): string {
 }
 
 export async function createCalendarEvent(booking: Booking): Promise<Booking> {
-  const response = await calendar.events.insert(
-    {
-      calendarId,
-      requestBody: {
-        summary: getSummary(booking),
-        description: getDescription(booking),
-        start: { date: booking.startDate },
-        end: { date: booking.endDate },
-      },
-    },
-    {}
+  const exclusiveEndDate = dateFormatBackend(
+    getNextDay(new Date(booking.endDate))
   )
+  const data = {
+    calendarId,
+    requestBody: {
+      summary: getSummary(booking),
+      description: getDescription(booking),
+      start: { date: booking.startDate },
+      end: { date: exclusiveEndDate },
+    },
+  }
+  const response = await calendar.events.insert(data, {})
 
   booking.calendarEventId = response.data.id