Calendar

Provides an API for interacting with the device's system calendars, events, reminders, and associated records.

Platform Compatibility

Android Device	Android Emulator	iOS Device	iOS Simulator	Web

Installation

expo install expo-calendar

If you're installing this in a bare React Native app, you should also follow these additional installation instructions.

Configuration

You must add the following permissions to your app.json.

Android requires READ_CALENDAR & WRITE_CALENDAR inside the expo.android.permissions array.
iOS requires the NSRemindersUsageDescription key be added to expo.devs.infoPlist with a string value describing the reason for the permission request.

Usage

import React, { useEffect } from 'react';
import { StyleSheet, View, Text, Button, Platform } from 'react-native';
import * as Calendar from 'expo-calendar';

export default function App() {
  useEffect(() => {
    (async () => {
      const { status } = await Calendar.requestCalendarPermissionsAsync();
      if (status === 'granted') {
        const calendars = await Calendar.getCalendarsAsync(Calendar.EntityTypes.EVENT);
        console.log('Here are all your calendars:');
        console.log({ calendars });
      }
    })();
  }, []);

  return (
    <View style={styles.container}>
      <Text>Calendar Module Example</Text>
      <Button title="Create a new calendar" onPress={createCalendar} />
    </View>
  );
}

async function getDefaultCalendarSource() {
  const calendars = await Calendar.getCalendarsAsync(Calendar.EntityTypes.EVENT);
  const defaultCalendars = calendars.filter(each => each.source.name === 'Default');
  return defaultCalendars[0].source;
}

async function createCalendar() {
  const defaultCalendarSource =
    Platform.OS === 'ios'
      ? await getDefaultCalendarSource()
      : { isLocalAccount: true, name: 'Expo Calendar' };
  const newCalendarID = await Calendar.createCalendarAsync({
    title: 'Expo Calendar',
    color: 'blue',
    entityType: Calendar.EntityTypes.EVENT,
    sourceId: defaultCalendarSource.id,
    source: defaultCalendarSource,
    name: 'internalCalendarName',
    ownerAccount: 'personal',
    accessLevel: Calendar.CalendarAccessLevel.OWNER,
  });
  console.log(`Your new calendar ID is: ${newCalendarID}`);
}

%%placeholder-start%%const styles = StyleSheet.create({ ... }); %%placeholder-end%%const styles = StyleSheet.create({
  container: {
    flex: 1,
    backgroundColor: '#fff',
    alignItems: 'center',
    justifyContent: 'space-around',
  },
});

API

import * as Calendar from 'expo-calendar';

Methods

`Calendar.isAvailableAsync()`

Returns whether the Calendar API is enabled on the current device. This does not check the app permissions.

Returns

Async boolean, indicating whether the Calendar API is available on the current device. Currently this resolves true on iOS and Android only.

`Calendar.getCalendarsAsync(entityType)`

Gets an array of calendar objects with details about the different calendars stored on the device.

Arguments

entityType (string) -- (iOS only) Not required, but if defined, filters the returned calendars to a specific entity type. Possible values are Calendar.EntityTypes.EVENT (for calendars shown in the Calendar app) and Calendar.EntityTypes.REMINDER (for the Reminders app). Note: if not defined, you will need both permissions: CALENDAR and REMINDERS.

Returns

An array of calendar objects matching the provided entity type (if provided).

`Calendar.getDefaultCalendarAsync()`

iOS only. Gets an instance of the default calendar object.

Returns

A promise resolving to calendar object that is the user's default calendar.

`Calendar.requestCalendarPermissionsAsync()`

Asks the user to grant permissions for accessing user's calendars.

Returns

A promise that resolves to an object of type PermissionResponse.

`Calendar.requestRemindersPermissionsAsync()`

iOS only. Asks the user to grant permissions for accessing user's reminders.

Returns

A promise that resolves to an object of type PermissionResponse.

`Calendar.getCalendarPermissionsAsync()`

Checks user's permissions for accessing user's calendars.

Returns

A promise that resolves to an object of type PermissionResponse.

`Calendar.getRemindersPermissionsAsync()`

iOS only. Checks user's permissions for accessing user's reminders.

Returns

A promise that resolves to an object of type PermissionResponse.

`Calendar.createCalendarAsync(details)`

Creates a new calendar on the device, allowing events to be added later and displayed in the OS Calendar app.

Arguments

details (object) --
A map of details for the calendar to be created (see below for a description of these fields):
- title (string) -- Required
- color (string) -- Required
- entityType (string) -- Required (iOS only)
- sourceId (string) -- (iOS only) ID of the source to be used for the calendar. Likely the same as the source for any other locally stored calendars.
- source (object) -- Required (Android only). Object representing the source to be used for the calendar.
  - isLocalAccount (boolean) -- Whether this source is the local phone account. Must be true if type is undefined.
  - name (string) -- Required. Name for the account that owns this calendar and was used to sync the calendar to the device.
  - type (string) -- Type of the account that owns this calendar and was used to sync it to the device. If isLocalAccount is falsy then this must be defined, and must match an account on the device along with name, or the OS will delete the calendar.
- name (string) -- Required (Android only)
- ownerAccount (string) -- Required (Android only)
- timeZone (string) -- (Android only)
- allowedAvailabilities (array) -- (Android only)
- allowedReminders (array) -- (Android only)
- allowedAttendeeTypes (array) -- (Android only)
- isVisible (boolean) -- (Android only)
- isSynced (boolean) -- (Android only) Whether or not the calendar is synced from a remote source. Unexpected behavior may occur if this is not set to true.
- accessLevel (string) -- (Android only)

Returns

A string representing the ID of the newly created calendar.

`Calendar.updateCalendarAsync(id, details)`

Updates the provided details of an existing calendar stored on the device. To remove a property, explicitly set it to null in details.

Arguments

id (string) -- ID of the calendar to update. Required.
details (object) --
A map of properties to be updated (see below for a description of these fields):
- title (string)
- sourceId (string) -- (iOS only)
- color (string) -- (iOS only)
- name (string) -- (Android only)
- isVisible (boolean) -- (Android only)
- isSynced (boolean) -- (Android only)

`Calendar.deleteCalendarAsync(id)`

Deletes an existing calendar and all associated events/reminders/attendees from the device. Use with caution.

Arguments

id (string) -- ID of the calendar to delete.

`Calendar.getEventsAsync(calendarIds, startDate, endDate)`

Returns all events in a given set of calendars over a specified time period. The filtering has slightly different behavior per-platform -- on iOS, all events that overlap at all with the [startDate, endDate] interval are returned, whereas on Android, only events that begin on or after the startDate and end on or before the endDate will be returned.

Arguments

calendarIds (array) -- Array of IDs of calendars to search for events in. Required.
startDate (Date) -- Beginning of time period to search for events in. Required.
endDate (Date) -- End of time period to search for events in. Required.

Returns

An array of event objects matching the search criteria.

`Calendar.getEventAsync(id, recurringEventOptions)`

Returns a specific event selected by ID. If a specific instance of a recurring event is desired, the start date of this instance must also be provided, as instances of recurring events do not have their own unique and stable IDs on either iOS or Android.

Arguments

id (string) -- ID of the event to return. Required.
recurringEventOptions (object) --
A map of options for recurring events:
- instanceStartDate (Date) -- Date object representing the start time of the desired instance, if looking for a single instance of a recurring event. If this is not provided and id represents a recurring event, the first instance of that event will be returned by default.

Returns

An event object matching the provided criteria, if one exists.

`Calendar.createEventAsync(calendarId, details)`

Creates a new event on the specified calendar.

Arguments

calendarId (string) -- ID of the calendar to create this event in. Required.
details (object) --
A map of details for the event to be created (see below for a description of these fields):
- title (string)
- startDate (Date) -- Required.
- endDate (Date) -- Required.
- allDay (boolean)
- location (string)
- notes (string)
- alarms (Array\<Alarm>)
- recurrenceRule (RecurrenceRule)
- availability (string)
- timeZone (string) -- Required on Android.
- endTimeZone (string) -- (Android only)
- url (string) -- (iOS only)
- organizerEmail (string) -- (Android only)
- accessLevel (string) -- (Android only)
- guestsCanModify (boolean) -- (Android only)
- guestsCanInviteOthers (boolean) -- (Android only)
- guestsCanSeeGuests (boolean) -- (Android only)

Returns

A string representing the ID of the newly created event.

`Calendar.updateEventAsync(id, details, recurringEventOptions)`

Updates the provided details of an existing calendar stored on the device. To remove a property, explicitly set it to null in details.

Arguments

id (string) -- ID of the event to be updated. Required.
details (object) --
A map of properties to be updated (see below for a description of these fields):
- title (string)
- startDate (Date)
- endDate (Date)
- allDay (boolean)
- location (string)
- notes (string)
- alarms (Array\<Alarm>)
- recurrenceRule (RecurrenceRule)
- availability (string)
- timeZone (string)
- endTimeZone (string) -- (Android only)
- url (string) -- (iOS only)
- organizerEmail (string) -- (Android only)
- accessLevel (string) -- (Android only)
- guestsCanModify (boolean) -- (Android only)
- guestsCanInviteOthers (boolean) -- (Android only)
- guestsCanSeeGuests (boolean) -- (Android only)
recurringEventOptions (object) --
A map of options for recurring events:
- instanceStartDate (Date) -- Date object representing the start time of the desired instance, if wanting to update a single instance of a recurring event. If this is not provided and id represents a recurring event, the first instance of that event will be updated by default.
- futureEvents (boolean) -- Whether or not future events in the recurring series should also be updated. If true, will apply the given changes to the recurring instance specified by instanceStartDate and all future events in the series. If false, will only apply the given changes to the instance specified by instanceStartDate.

`Calendar.deleteEventAsync(id, recurringEventOptions)`

Deletes an existing event from the device. Use with caution.

Arguments

id (string) -- ID of the event to be deleted. Required.
recurringEventOptions (object) --
A map of options for recurring events:
- instanceStartDate (Date) -- Date object representing the start time of the desired instance, if wanting to delete a single instance of a recurring event. If this is not provided and id represents a recurring event, the first instance of that event will be deleted by default.
- futureEvents (boolean) -- Whether or not future events in the recurring series should also be deleted. If true, will delete the instance specified by instanceStartDate and all future events in the series. If false, will only delete the instance specified by instanceStartDate.

`Calendar.getAttendeesForEventAsync(eventId, recurringEventOptions)`

Gets all attendees for a given event (or instance of a recurring event).

Arguments

eventId (string) -- ID of the event to return attendees for. Required.
recurringEventOptions (object) --
A map of options for recurring events:
- instanceStartDate (Date) -- Date object representing the start time of the desired instance, if looking for a single instance of a recurring event. If this is not provided and eventId represents a recurring event, the attendees of the first instance of that event will be returned by default.

Returns

An array of attendee objects associated with the specified event.

`Calendar.createAttendeeAsync(eventId, details)`

Available on Android only. Creates a new attendee record and adds it to the specified event. Note that if eventId specifies a recurring event, this will add the attendee to every instance of the event.

Arguments

eventId (string) -- ID of the event to add this attendee to. Required.
details (object) --
A map of details for the attendee to be created (see below for a description of these fields):
- id (string) Required.
- email (string) Required.
- name (string)
- role (string) Required.
- status (string) Required.
- type (string) Required.

Returns

A string representing the ID of the newly created attendee record.

`Calendar.updateAttendeeAsync(id, details)`

Available on Android only. Updates an existing attendee record. To remove a property, explicitly set it to null in details.

Arguments

id (string) -- ID of the attendee record to be updated. Required.
details (object) --
A map of properties to be updated (see below for a description of these fields):
- id (string)
- email (string)
- name (string)
- role (string)
- status (string)
- type (string)

`Calendar.deleteAttendeeAsync(id)`

Available on Android only. Deletes an existing attendee record from the device. Use with caution.

Arguments

id (string) -- ID of the attendee to delete.

`Calendar.getRemindersAsync(calendarIds, status, startDate, endDate)`

Available on iOS only. Returns a list of reminders matching the provided criteria. If startDate and endDate are defined, returns all reminders that overlap at all with the [startDate, endDate] interval -- i.e. all reminders that end after the startDate or begin before the endDate.

Arguments

calendarIds (array) -- Array of IDs of calendars to search for reminders in. Required.
status (string) -- One of Calendar.ReminderStatus.COMPLETED or Calendar.ReminderStatus.INCOMPLETE.
startDate (Date) -- Beginning of time period to search for reminders in. Required if status is defined.
endDate (Date) -- End of time period to search for reminders in. Required if status is defined.

Returns

An array of reminder objects matching the search criteria.

`Calendar.getReminderAsync(id)`

Available on iOS only. Returns a specific reminder selected by ID.

Arguments

id (string) -- ID of the reminder to return. Required.

Returns

An reminder object matching the provided ID, if one exists.

`Calendar.createReminderAsync(calendarId, details)`

Available on iOS only. Creates a new reminder on the specified calendar.

Arguments

calendarId (string) -- ID of the calendar to create this reminder in (or null to add the calendar to the OS-specified default calendar for reminders). Required.
details (object) --
A map of details for the reminder to be created: (see below for a description of these fields)
- title (string)
- startDate (Date)
- dueDate (Date)
- completed (boolean)
- completionDate (Date)
- location (string)
- notes (string)
- alarms (array)
- recurrenceRule (RecurrenceRule)
- timeZone (string)
- url (string)

Returns

A string representing the ID of the newly created reminder.

`Calendar.updateReminderAsync(id, details)`

Available on iOS only. Updates the provided details of an existing reminder stored on the device. To remove a property, explicitly set it to null in details.

Arguments

id (string) -- ID of the reminder to be updated. Required.
details (object) --
A map of properties to be updated (see below for a description of these fields):
- title (string)
- startDate (Date)
- dueDate (Date)
- completionDate (Date) -- Setting this property of a nonnull Date will automatically set the reminder's completed value to true.
- location (string)
- notes (string)
- alarms (array)
- recurrenceRule (RecurrenceRule)
- timeZone (string)
- url (string)

`Calendar.deleteReminderAsync(id)`

Available on iOS only. Deletes an existing reminder from the device. Use with caution.

Arguments

id (string) -- ID of the reminder to be deleted. Required.

`Calendar.getSourcesAsync()`

Available on iOS only.

Returns

An array of source objects all sources for calendars stored on the device.

`Calendar.getSourceAsync(id)`

Available on iOS only. Returns a specific source selected by ID.

Arguments

id (string) -- ID of the source to return. Required.

Returns

A source object matching the provided ID, if one exists.

`Calendar.openEventInCalendar(id)`

Available on Android only. Sends an intent to open the specified event in the OS Calendar app.

Arguments

id (string) -- ID of the event to open. Required.

Object Types

Calendar

A calendar record upon which events (or, on iOS, reminders) can be stored. Settings here apply to the calendar as a whole and how its events are displayed in the OS calendar app.

Field name	Type	Platforms	Description	Possible values
id	string	both	Internal ID that represents this calendar on the device
title	string	both	Visible name of the calendar
entityType	string	iOS	Whether the calendar is used in the Calendar or Reminders OS app	`Calendar.EntityTypes.EVENT`, `Calendar.EntityTypes.REMINDER`
source	Source	both	Object representing the source to be used for the calendar
color	string	both	Color used to display this calendar's events
allowsModifications	boolean	both	Boolean value that determines whether this calendar can be modified
type	string	iOS	Type of calendar this object represents	`Calendar.CalendarType.LOCAL`, `Calendar.CalendarType.CALDAV`, `Calendar.CalendarType.EXCHANGE`, `Calendar.CalendarType.SUBSCRIBED`, `Calendar.CalendarType.BIRTHDAYS`, `Calendar.CalendarType.UNKNOWN`
isPrimary	boolean	Android	Boolean value indicating whether this is the device's primary calendar
name	_string	null_	Android	Internal system name of the calendar
ownerAccount	string	Android	Name for the account that owns this calendar
timeZone	string	Android	Time zone for the calendar
allowedAvailabilities	array	both	Availability types that this calendar supports	array of `Calendar.Availability.BUSY`, `Calendar.Availability.FREE`, `Calendar.Availability.TENTATIVE`, `Calendar.Availability.UNAVAILABLE` (iOS only), `Calendar.Availability.NOT_SUPPORTED` (iOS only)
allowedReminders	array	Android	Alarm methods that this calendar supports	array of `Calendar.AlarmMethod.ALARM`, `Calendar.AlarmMethod.ALERT`, `Calendar.AlarmMethod.EMAIL`, `Calendar.AlarmMethod.SMS`, `Calendar.AlarmMethod.DEFAULT`
allowedAttendeeTypes	array	Android	Attendee types that this calendar supports	array of `Calendar.AttendeeType.UNKNOWN` (iOS only), `Calendar.AttendeeType.PERSON` (iOS only), `Calendar.AttendeeType.ROOM` (iOS only), `Calendar.AttendeeType.GROUP` (iOS only), `Calendar.AttendeeType.RESOURCE`, `Calendar.AttendeeType.OPTIONAL` (Android only), `Calendar.AttendeeType.REQUIRED` (Android only), `Calendar.AttendeeType.NONE` (Android only)
isVisible	boolean	Android	Indicates whether the OS displays events on this calendar
isSynced	boolean	Android	Indicates whether this calendar is synced and its events stored on the device
accessLevel	string	Android	Level of access that the user has for the calendar	`Calendar.CalendarAccessLevel.CONTRIBUTOR`, `Calendar.CalendarAccessLevel.EDITOR`, `Calendar.CalendarAccessLevel.FREEBUSY`, `Calendar.CalendarAccessLevel.OVERRIDE`, `Calendar.CalendarAccessLevel.OWNER`, `Calendar.CalendarAccessLevel.READ`, `Calendar.CalendarAccessLevel.RESPOND`, `Calendar.CalendarAccessLevel.ROOT`, `Calendar.CalendarAccessLevel.NONE`

Event

An event record, or a single instance of a recurring event. On iOS, used in the Calendar app.

Field name	Type	Platforms	Description	Possible values
id	string	both	Internal ID that represents this event on the device
calendarId	string	both	ID of the calendar that contains this event
title	string	both	Visible name of the event
startDate	Date	both	Date object or string representing the time when the event starts
endDate	Date	both	Date object or string representing the time when the event ends
allDay	boolean	both	Whether the event is displayed as an all-day event on the calendar
location	string	both	Location field of the event
notes	string	both	Description or notes saved with the event
alarms	array	both	Array of Alarm objects which control automated reminders to the user
recurrenceRule	RecurrenceRule	both	Object representing rules for recurring or repeating events. Null for one-time events.
availability	string	both	The availability setting for the event	`Calendar.Availability.BUSY`, `Calendar.Availability.FREE`, `Calendar.Availability.TENTATIVE`, `Calendar.Availability.UNAVAILABLE` (iOS only), `Calendar.Availability.NOT_SUPPORTED` (iOS only)
timeZone	string	both	Time zone the event is scheduled in
endTimeZone	string	Android	Time zone for the event end time
url	string	iOS	URL for the event
creationDate	string	iOS	Date when the event record was created
lastModifiedDate	string	iOS	Date when the event record was last modified
originalStartDate	string	iOS	For recurring events, the start date for the first (original) instance of the event
isDetached	boolean	iOS	Boolean value indicating whether or not the event is a detached (modified) instance of a recurring event
status	string	iOS	Status of the event	`Calendar.EventStatus.NONE`, `Calendar.EventStatus.CONFIRMED`, `Calendar.EventStatus.TENTATIVE`, `Calendar.EventStatus.CANCELED`
organizer	Attendee	iOS	Organizer of the event, as an Attendee object
organizerEmail	string	Android	Email address of the organizer of the event
accessLevel	string	Android	User's access level for the event	`Calendar.EventAccessLevel.CONFIDENTIAL`, `Calendar.EventAccessLevel.PRIVATE`, `Calendar.EventAccessLevel.PUBLIC`, `Calendar.EventAccessLevel.DEFAULT`
guestsCanModify	boolean	Android	Whether invited guests can modify the details of the event
guestsCanInviteOthers	boolean	Android	Whether invited guests can invite other guests
guestsCanSeeGuests	boolean	Android	Whether invited guests can see other guests
originalId	string	Android	For detached (modified) instances of recurring events, the ID of the original recurring event
instanceId	string	Android	For instances of recurring events, volatile ID representing this instance; not guaranteed to always refer to the same instance

Reminder

A reminder record, used in the iOS Reminders app. No direct analog on Android.

Field name	Type	Description
id	string	Internal ID that represents this reminder on the device
calendarId	string	ID of the calendar that contains this reminder
title	string	Visible name of the reminder
startDate	Date	Date object or string representing the start date of the reminder task
dueDate	Date	Date object or string representing the time when the reminder task is due
completed	boolean	Indicates whether or not the task has been completed
completionDate	Date	Date object or string representing the date of completion, if `completed` is `true`
location	string	Location field of the reminder
notes	string	Description or notes saved with the reminder
alarms	array	Array of Alarm objects which control automated alarms to the user about the task
recurrenceRule	RecurrenceRule	Object representing rules for recurring or repeated reminders. Null for one-time tasks.
timeZone	string	Time zone the reminder is scheduled in
url	string	URL for the reminder
creationDate	string	Date when the reminder record was created
lastModifiedDate	string	Date when the reminder record was last modified

Attendee

A person or entity that is associated with an event by being invited or fulfilling some other role.

Field name	Type	Platforms	Description	Possible values
id	string	Android	Internal ID that represents this attendee on the device
email	string	Android	Email address of the attendee
name	string	both	Displayed name of the attendee
role	string	both	Role of the attendee at the event	`Calendar.AttendeeRole.UNKNOWN` (iOS only), `Calendar.AttendeeRole.REQUIRED` (iOS only), `Calendar.AttendeeRole.OPTIONAL` (iOS only), `Calendar.AttendeeRole.CHAIR` (iOS only), `Calendar.AttendeeRole.NON_PARTICIPANT` (iOS only), `Calendar.AttendeeRole.ATTENDEE` (Android only), `Calendar.AttendeeRole.ORGANIZER` (Android only), `Calendar.AttendeeRole.PERFORMER` (Android only), `Calendar.AttendeeRole.SPEAKER` (Android only), `Calendar.AttendeeRole.NONE` (Android only)
status	string	both	Status of the attendee in relation to the event	`Calendar.AttendeeStatus.ACCEPTED`, `Calendar.AttendeeStatus.DECLINED`, `Calendar.AttendeeStatus.TENTATIVE`, `Calendar.AttendeeStatus.DELEGATED` (iOS only), `Calendar.AttendeeStatus.COMPLETED` (iOS only), `Calendar.AttendeeStatus.IN_PROCESS` (iOS only), `Calendar.AttendeeStatus.UNKNOWN` (iOS only), `Calendar.AttendeeStatus.PENDING` (iOS only), `Calendar.AttendeeStatus.INVITED` (Android only), `Calendar.AttendeeStatus.NONE` (Android only)
type	string	both	Type of the attendee	`Calendar.AttendeeType.UNKNOWN` (iOS only), `Calendar.AttendeeType.PERSON` (iOS only), `Calendar.AttendeeType.ROOM` (iOS only), `Calendar.AttendeeType.GROUP` (iOS only), `Calendar.AttendeeType.RESOURCE`, `Calendar.AttendeeType.OPTIONAL` (Android only), `Calendar.AttendeeType.REQUIRED` (Android only), `Calendar.AttendeeType.NONE` (Android only)
url	string	iOS	URL for the attendee
isCurrentUser	boolean	iOS	Indicates whether or not this attendee is the current OS user

RecurrenceRule

A recurrence rule for events or reminders, allowing the same calendar item to recur multiple times. This interface is based on the iOS interface which is in turn based on the iCal RFC so you can refer to those to learn more about this potentially complex interface.

Not all of the combinations make sense. For example, when frequency is DAILY, setting daysOfTheMonth makes no sense.

Field name	Type	Description	Possible values
frequency	string	How often the calendar item should recur	`Calendar.Frequency.DAILY`, `Calendar.Frequency.WEEKLY`, `Calendar.Frequency.MONTHLY`, `Calendar.Frequency.YEARLY`
interval	number	Interval at which the calendar item should recur. For example, an `interval: 2` with `frequency: DAILY` would yield an event that recurs every other day. Defaults to `1`.
endDate	Date	Date on which the calendar item should stop recurring; overrides `occurrence` if both are specified
occurrence	number	Number of times the calendar item should recur before stopping
daysOfTheWeek	array	(Optional, iOS only) the days of the week the event should recur on. An array of `{ dayOfTheWeek: DayOfTheWeek; weekNumber?: number }`	`dayOfTheWeek`: Sunday to Saturday (`enum DayOfTheWeek`), `weekNumber`: -53 to 53 (0 ignores this field, and a negative indicates a value from the end of the range).
daysOfTheMonth	number[]	(Optional, iOS only) They days of the month this event occurs on	-31 to 31 (not including 0). Negative indicates a value from the end of the range. This field is only valid for `Calendar.Frequency.Monthly`.
monthsOfTheYear	MonthOfTheYear[]	(Optional, iOS only) The months this event occurs on.	This field is only valid for `Calendar.Frequency.Yearly`.
weeksOfTheYear	number[]	(Optional, iOS only) The weeks of the year this event occurs on.	-53 to 53 (not including 0). Negative indicates a value from the end of the range. This field is only valid for `Calendar.Frequency.Yearly`.
daysOfTheYear	number[]	(Optional, iOS only) The days of the year this event occurs on.	-366 to 366 (not including 0). Negative indicates a value from the end of the range. This field is only valid for `Calendar.Frequency.Yearly`.
setPositions	number[]	(Optional, iOS only) An array of numbers that filters which recurrences to include. For example, for an event that recurs every Monday, passing 2 here will make it recur every other Monday.	-366 to 366 (not including 0). Negative indicates a value from the end of the range. This field is only valid for `Calendar.Frequency.Yearly`.

Alarm

A method for having the OS automatically remind the user about an calendar item

Field name	Type	Platforms	Description	Possible values
absoluteDate	Date	iOS	Date object or string representing an absolute time the alarm should occur; overrides `relativeOffset` and `structuredLocation` if specified alongside either
relativeOffset	number	both	Number of minutes from the `startDate` of the calendar item that the alarm should occur; use negative values to have the alarm occur before the `startDate`
method	string	Android	Method of alerting the user that this alarm should use; on iOS this is always a notification	`Calendar.AlarmMethod.ALARM`, `Calendar.AlarmMethod.ALERT`, `Calendar.AlarmMethod.EMAIL`, `Calendar.AlarmMethod.SMS`, `Calendar.AlarmMethod.DEFAULT`

Source

A source account that owns a particular calendar. Expo apps will typically not need to interact with Source objects.

Field name	Type	Platforms	Description	Possible values
id	string	iOS	Internal ID that represents this source on the device
name	string	both	Name for the account that owns this calendar
type	string	both	Type of account that owns this calendar	on iOS, one of `Calendar.SourceType.LOCAL`, `Calendar.SourceType.EXCHANGE`, `Calendar.SourceType.CALDAV`, `Calendar.SourceType.MOBILEME`, `Calendar.SourceType.SUBSCRIBED`, or `Calendar.SourceType.BIRTHDAYS`
isLocalAccount	boolean	Android	Whether this source is the local phone account

Enum Types

`Calendar.DayOfTheWeek`

DayOfTheWeek	Value
`DayOfTheWeek.Sunday`	1
`DayOfTheWeek.Monday`	2
`DayOfTheWeek.Tuesday`	3
`DayOfTheWeek.Wednesday`	4
`DayOfTheWeek.Thursday`	5
`DayOfTheWeek.Friday`	6
`DayOfTheWeek.Saturday`	7

`Calendar.MonthOfTheYear`

MonthOfTheYear	Value
`MonthOfTheYear.January`	1
`MonthOfTheYear.February`	2
`MonthOfTheYear.March`	3
`MonthOfTheYear.April`	4
`MonthOfTheYear.May`	5
`MonthOfTheYear.June`	6
`MonthOfTheYear.July`	7
`MonthOfTheYear.August`	8
`MonthOfTheYear.September`	9
`MonthOfTheYear.October`	10
`MonthOfTheYear.November`	11
`MonthOfTheYear.December`	12