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JSCalendar: Converting from and to iCalendar
draft-ietf-calext-jscalendar-icalendar-04

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Authors Neil Jenkins , Robert Stepanek , Michael Douglass
Last updated 2021-02-20
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draft-ietf-calext-jscalendar-icalendar-04
Calendaring extensions                                        N. Jenkins
Internet-Draft                                               R. Stepanek
Intended status: Standards Track                                FastMail
Expires: August 25, 2021                                     M. Douglass
                                                                     BCS
                                                       February 21, 2021

              JSCalendar: Converting from and to iCalendar
               draft-ietf-calext-jscalendar-icalendar-04

Abstract

   This document provides the required methods for converting JSCalendar
   from and to iCalendar.

Status of This Memo

   This Internet-Draft is submitted in full conformance with the
   provisions of BCP 78 and BCP 79.

   Internet-Drafts are working documents of the Internet Engineering
   Task Force (IETF).  Note that other groups may also distribute
   working documents as Internet-Drafts.  The list of current Internet-
   Drafts is at https://datatracker.ietf.org/drafts/current/.

   Internet-Drafts are draft documents valid for a maximum of six months
   and may be updated, replaced, or obsoleted by other documents at any
   time.  It is inappropriate to use Internet-Drafts as reference
   material or to cite them other than as "work in progress."

   This Internet-Draft will expire on August 25, 2021.

Copyright Notice

   Copyright (c) 2021 IETF Trust and the persons identified as the
   document authors.  All rights reserved.

   This document is subject to BCP 78 and the IETF Trust's Legal
   Provisions Relating to IETF Documents
   (https://trustee.ietf.org/license-info) in effect on the date of
   publication of this document.  Please review these documents
   carefully, as they describe your rights and restrictions with respect
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   the Trust Legal Provisions and are provided without warranty as
   described in the Simplified BSD License.

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Table of Contents

   1.  Introduction  . . . . . . . . . . . . . . . . . . . . . . . .   3
     1.1.  Note (to be deleted later)  . . . . . . . . . . . . . . .   4
     1.2.  Motivation  . . . . . . . . . . . . . . . . . . . . . . .   4
     1.3.  Scope and caveats . . . . . . . . . . . . . . . . . . . .   4
     1.4.  Notational Conventions  . . . . . . . . . . . . . . . . .   5
   2.  New iCalendar parameters  . . . . . . . . . . . . . . . . . .   5
     2.1.  FRACTIONAL parameter  . . . . . . . . . . . . . . . . . .   5
   3.  iCalendar pre-processing  . . . . . . . . . . . . . . . . . .   6
   4.  Translating iCalendar components to JSCalendar  . . . . . . .   7
     4.1.  VALARM  . . . . . . . . . . . . . . . . . . . . . . . . .   7
     4.2.  VCALENDAR . . . . . . . . . . . . . . . . . . . . . . . .  10
     4.3.  VEVENT  . . . . . . . . . . . . . . . . . . . . . . . . .  11
     4.4.  VLOCATION . . . . . . . . . . . . . . . . . . . . . . . .  11
     4.5.  VTIMEZONE, STANDARD, DAYLIGHT . . . . . . . . . . . . . .  12
     4.6.  VTODO . . . . . . . . . . . . . . . . . . . . . . . . . .  13
   5.  Translating iCalendar properties to JSCalendar  . . . . . . .  13
     5.1.  ATTACH  . . . . . . . . . . . . . . . . . . . . . . . . .  13
     5.2.  ATTENDEE  . . . . . . . . . . . . . . . . . . . . . . . .  13
     5.3.  CALSCALE  . . . . . . . . . . . . . . . . . . . . . . . .  16
     5.4.  CATEGORIES  . . . . . . . . . . . . . . . . . . . . . . .  16
     5.5.  CLASS . . . . . . . . . . . . . . . . . . . . . . . . . .  16
     5.6.  COLOR . . . . . . . . . . . . . . . . . . . . . . . . . .  17
     5.7.  COMMENT . . . . . . . . . . . . . . . . . . . . . . . . .  17
     5.8.  COMPLETED . . . . . . . . . . . . . . . . . . . . . . . .  17
     5.9.  CONCEPT . . . . . . . . . . . . . . . . . . . . . . . . .  17
     5.10. CONFERENCE  . . . . . . . . . . . . . . . . . . . . . . .  18
     5.11. CONTACT . . . . . . . . . . . . . . . . . . . . . . . . .  18
     5.12. CREATED . . . . . . . . . . . . . . . . . . . . . . . . .  19
     5.13. DESCRIPTION . . . . . . . . . . . . . . . . . . . . . . .  19
     5.14. DTEND, DTSTART, DUE, DURATION . . . . . . . . . . . . . .  20
     5.15. EXDATE  . . . . . . . . . . . . . . . . . . . . . . . . .  23
     5.16. EXRULE  . . . . . . . . . . . . . . . . . . . . . . . . .  23
     5.17. DTSTAMP and LAST-MODIFIED . . . . . . . . . . . . . . . .  23
     5.18. GEO . . . . . . . . . . . . . . . . . . . . . . . . . . .  23
     5.19. IMAGE . . . . . . . . . . . . . . . . . . . . . . . . . .  23
     5.20. LOCATION  . . . . . . . . . . . . . . . . . . . . . . . .  24
     5.21. METHOD  . . . . . . . . . . . . . . . . . . . . . . . . .  24
     5.22. ORGANIZER . . . . . . . . . . . . . . . . . . . . . . . .  24
     5.23. PERCENT-COMPLETE  . . . . . . . . . . . . . . . . . . . .  24
     5.24. PRIORITY  . . . . . . . . . . . . . . . . . . . . . . . .  27
     5.25. PRODID  . . . . . . . . . . . . . . . . . . . . . . . . .  28
     5.26. RECURRENCE-ID . . . . . . . . . . . . . . . . . . . . . .  28
     5.27. RELATED-TO  . . . . . . . . . . . . . . . . . . . . . . .  28
     5.28. REQUEST-STATUS  . . . . . . . . . . . . . . . . . . . . .  29
     5.29. RESOURCES . . . . . . . . . . . . . . . . . . . . . . . .  29
     5.30. RDATE . . . . . . . . . . . . . . . . . . . . . . . . . .  30

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     5.31. RRULE . . . . . . . . . . . . . . . . . . . . . . . . . .  30
     5.32. SEQUENCE  . . . . . . . . . . . . . . . . . . . . . . . .  34
     5.33. STATUS  . . . . . . . . . . . . . . . . . . . . . . . . .  34
     5.34. STRUCTURED-DATA . . . . . . . . . . . . . . . . . . . . .  34
     5.35. SUMMARY . . . . . . . . . . . . . . . . . . . . . . . . .  35
     5.36. TRANSP  . . . . . . . . . . . . . . . . . . . . . . . . .  35
     5.37. UID . . . . . . . . . . . . . . . . . . . . . . . . . . .  36
     5.38. URL . . . . . . . . . . . . . . . . . . . . . . . . . . .  36
   6.  Translating iCalendar Recurrences . . . . . . . . . . . . . .  36
     6.1.  Translating iCalendar Recurrences: Simple objects with
           overrides . . . . . . . . . . . . . . . . . . . . . . . .  36
     6.2.  Translating iCalendar Recurrences: Overrides with no
           master  . . . . . . . . . . . . . . . . . . . . . . . . .  36
   7.  Translating iCalendar: Further examples . . . . . . . . . . .  36
     7.1.  Recurring event with ATTACH . . . . . . . . . . . . . . .  37
     7.2.  Simple event with CONTACT . . . . . . . . . . . . . . . .  39
     7.3.  Simple event with RESOURCES . . . . . . . . . . . . . . .  40
     7.4.  Recurring event. Attendees only in overrides  . . . . . .  40
   8.  Security Considerations . . . . . . . . . . . . . . . . . . .  43
   9.  IANA Considerations . . . . . . . . . . . . . . . . . . . . .  43
   10. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . .  44
   11. References  . . . . . . . . . . . . . . . . . . . . . . . . .  44
     11.1.  Normative References . . . . . . . . . . . . . . . . . .  44
     11.2.  Informative References . . . . . . . . . . . . . . . . .  45
   Appendix A.  Outdated document sections . . . . . . . . . . . . .  45
     A.1.  Translating JSCalendar properties to iCalendar components  45
       A.1.1.  jsevent . . . . . . . . . . . . . . . . . . . . . . .  45
       A.1.2.  jsgroup . . . . . . . . . . . . . . . . . . . . . . .  46
       A.1.3.  jstask  . . . . . . . . . . . . . . . . . . . . . . .  47
       A.1.4.  timezones . . . . . . . . . . . . . . . . . . . . . .  48
       A.1.5.  locations . . . . . . . . . . . . . . . . . . . . . .  49
       A.1.6.  participants  . . . . . . . . . . . . . . . . . . . .  49
     A.2.  Note  . . . . . . . . . . . . . . . . . . . . . . . . . .  50
     A.3.  JSEvent . . . . . . . . . . . . . . . . . . . . . . . . .  50
     A.4.  JSTask  . . . . . . . . . . . . . . . . . . . . . . . . .  51
     A.5.  JSGroup . . . . . . . . . . . . . . . . . . . . . . . . .  52
     A.6.  Common properties . . . . . . . . . . . . . . . . . . . .  52
       A.6.1.  Time properties and types . . . . . . . . . . . . . .  55
       A.6.2.  Locations . . . . . . . . . . . . . . . . . . . . . .  55
       A.6.3.  Participants  . . . . . . . . . . . . . . . . . . . .  56
     A.7.  Custom properties . . . . . . . . . . . . . . . . . . . .  57
   Authors' Addresses  . . . . . . . . . . . . . . . . . . . . . . .  58

1.  Introduction

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1.1.  Note (to be deleted later)

   This is still very much a work in progress.  There are
   implementations of the mapping but there may be changes over the
   coming weeks.

1.2.  Motivation

   The JSCalendar [draft-ietf-calext-jscalendar] data format is used to
   represent calendar data, and is meant as an alternative to the widely
   deployed iCalendar [RFC5545] data format.

   While new calendaring services and applications might use JSCalendar
   as their main data format to exchange calendaring data, they are
   likely to interoperate with services and clients that just support
   iCalendar.  Similarly, existing calendaring data is stored in
   iCalendar format in databases and other calendar stores, and
   providers and users might want to represent this data also in
   JSCalendar.  Lastly, there is a requirement to preserve custom
   iCalendar properties that have no equivalent in JSCalendar when
   converting between these formats.

   To support these use cases, this document provides the required
   approach when converting JSCalendar data from and to iCalendar.

1.3.  Scope and caveats

   JSCalendar and iCalendar have a lot of semantics in common, but they
   are not interchangeable formats:

   o  JSCalendar contains a richer data model to express calendar
      information such as event locations and participants.  while
      future iCalendar extensions may allow a direct mapping, for now
      there may be no representation directly in iCalendar of some
      properties.  These values may have to be extracted from a full
      copy of the iCalendar format provided as a property in the
      JSCalendar data.

   o  iCalendar may contain arbitrary, non-standardised data with custom
      properties/attributes.  These will be translated using the same
      approach as jCal.

   o  iCalendar has some obsolete features that have been removed from
      JSCalendar due to not being useful and/or supported in the real
      world (e.g. custom email alerts to send to random people).
      Translating these may lose some of the original fidelity.

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   o  Implementations may use a custom property to store data that could
      not be mapped directly in either direction in the original or a
      custom format, however this is not interoperable.

   Accordingly, this document defines a canonical translation between
   iCalendar and JSCalendar, and implementations MUST follow the
   approaches specified here when iCalendar data is represented in
   JSCalendar and vice-versa.

   This document defines mappings for the following specifications.

   o  Internet Calendaring and Scheduling Core Object Specification
      (iCalendar)

   o  iCalendar Transport-Independent Interoperability Protocol (iTIP)

   o  New Properties for iCalendar

   o  Event Publishing Extensions to iCalendar

   o  Support for iCalendar Relationships

   o  VALARM Extensions for iCalendar

   Therefore all of these specifications MUST be implemented to follow
   this specification.

1.4.  Notational Conventions

   The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
   "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
   document are to be interpreted as described in [RFC2119].

2.  New iCalendar parameters

2.1.  FRACTIONAL parameter

   Parameter name:  FRACTIONAL

   Purpose:  This parameter is used to contain a value with fractional
      seconds for time values and durations.  FRACTIONAL MUST NOT be
      used in date-time calculations or comparisons in iCalendar.  It is
      meant to preserve time precision on time values and duration with
      sub-second precision, without increasing the time value range
      within iCalendar.

   Description:  This parameter MAY be specified on properties of type
      DATE-TIME or DURATION.  It MUST be a valid iCalendar DATE-TIME or

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      DURATION value with the addition of fractional seconds.  The value
      MUST NOT be negative for durations but MAY be negative for alarm
      triggers.  iCalendar implementations SHOULD ignore this parameter
      in date time arithmetic.  Implementations MUST ignore presence of
      the FRACTIONAL parameter on RECURRENCE-ID properties when
      determining recurrence overrides.

      Applications receiving a property with a FRACTIONAL parameter MUST
      ensure its value is consistent with the value of the property.
      The property value must match:
      - a positive FRACTIONAL value rounded up to the next non-
      fractional second or
      - a negative FRACTIONAL value rounded down the next non-fractional
      second

      If the values do not match the the application MUST assume that
      the property value has been updated by an application that is
      unaware of the FRACTIONAL parameter.  The parameter should be
      ignored in this case.

   Format Definition:

   This parameter is defined by the following notation:

       fractional-param = DATE-TIME or DURATION

   Example:

       DTSTART;FRACTIONAL=20190605T133015.03:20190605T133015

3.  iCalendar pre-processing

   iCalendar uses a line-folding mechanism to limit lines of data to a
   maximum line length (typically 75 octets) to ensure the maximum
   likelihood of preserving data integrity as it is transported via
   various means (e.g., email) -- see Section 3.1 of [RFC5545].

   iCalendar data uses an "escape" character sequence for text values
   and property parameter values.  See Sections 3.1 and 3.3 of [RFC5545]
   as well as [RFC6868].

   There is a subtle difference in the number representations between
   JSON and iCalendar.  While in iCalendar, a number may have leading
   zeros, as well as a leading plus sign; this is not the case in JSON.
   Numbers should be represented in whatever way needed for the
   underlying format.

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   When converting from iCalendar to JSCalendar: First, iCalendar lines
   MUST be unfolded.  Afterwards, any iCalendar escaping MUST be
   unescaped.  Finally, JSON escaping, as described in Section 7 of
   [RFC7159], MUST be applied.  The reverse order applies when
   converting from JSCalendar to iCalendar, which is further described
   in Section ?.

   iCalendar uses a base64 encoding for binary data.  However, it does
   not restrict the encoding from being applied to non-binary value
   types.  So, the following rules are applied when processing a
   property with the "ENCODING" property parameter set to "BASE64":

   o  If the property value type is "BINARY", the base64 encoding MUST
      be preserved.

   o  If the value type is not "BINARY", the "ENCODING" property
      parameter MUST be removed, and the value MUST be base64 decoded.

   When base64 encoding is used, it MUST conform to Section 4 of
   [RFC4648], which is the base64 method used in [RFC5545].

   One key difference in the formatting of values used in iCalendar and
   JSCalendar is that, in JSCalendar, the specification uses date/time
   values aligned with the extended format of [ISO.8601.2004], which is
   more commonly used in Internet applications that make use of the JSON
   format.  The sections of this document describing the various date
   and time formats contain more information on the use of the complete
   representation, reduced accuracy, or truncated representation.

4.  Translating iCalendar components to JSCalendar

   This section is an alphabetic list of [RFC5545] components and how
   they are mapped to JSCalendar.

   At present VFREEBUSY and VJOURNAL are not mapped in jscalendar.

4.1.  VALARM

   An [RFC5545] VALARM component is mapped to a member of a JSCalendar
   "alerts" object with a type of "Alert" and a small id.

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     BEGIN: VEVENT
     ...
     BEGIN: VALARM
     ...
     END: VALARM
     BEGIN: VALARM
     ...
     END: VALARM
     END: VEVENT

     maps to

     {
       "@type": "jsevent",
       ...
       "alerts": {
         "1": {
           "@type": "Alert",
           ...
         },
         "2": {
           "@type": "Alert",
           ...
         }
       }
     }

   The [RFC5545] VALARM has a number of problems which are not carried
   over into JSCalendar.  Clients tend to choose how, and in some cases
   when to notify the user.

   For example, if the user has a smart-watch they may get tapped on the
   wrist.  The method of notification may depend on which device is
   being used and the context, for example a meeting or driving.

   Also, many clients are taking into consideration the travel time and
   notifying the user earlier if it seems necessary.

   Specifying that a client should send emails to all attendees is both
   annoying and dangerous.  Attendees have their own preferences for how
   and when they should be notified.

   Accordingly, the specification only allows for "display" and "email"
   actions and - other than specifying when - does not allow much else.
   Clients and/or servers will generally use the associated event or
   task title as identification.  User preferences generally indicate
   what actions they prefer.

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   An [RFC5545] ACTION property can take the defined values "AUDIO" /
   "DISPLAY" / "EMAIL" whereas the JSCalendar "action" property only
   supports "display" and "email".

   An "AUDIO" alarm SHOULD be mapped to a "display" alert.  Any
   attachment MUST be ignored.

   The [RFC5545] example VALARMs will be mapped as follows, assuming
   they are all in the same event:

     BEGIN:VEVENT
     ...
     BEGIN:VALARM
     TRIGGER;VALUE=DATE-TIME:19970317T133000Z
     REPEAT:4
     DURATION:PT15M
     ACTION:AUDIO
     ATTACH;FMTTYPE=audio/basic:ftp://example.com/pub/
     sounds/bell-01.aud
     END:VALARM
     BEGIN:VALARM
     TRIGGER:-PT30M
     REPEAT:2
     DURATION:PT15M
     ACTION:DISPLAY
     DESCRIPTION:Breakfast meeting with executive\n
      team at 8:30 AM EST.
     END:VALARM
     BEGIN:VALARM
     TRIGGER;RELATED=END:-P2D
     ACTION:EMAIL
     ATTENDEE:mailto:john_doe@example.com
     SUMMARY:*** REMINDER: SEND AGENDA FOR WEEKLY STAFF MEETING ***
     DESCRIPTION:A draft agenda needs to be sent out to the attendees
     to the weekly managers meeting (MGR-LIST). Attached is a
     pointer the document template for the agenda file.
     ATTACH;FMTTYPE=application/msword:http://example.com/
     templates/agenda.doc
     END:VALARM
     END:VEVENT

     maps to

     {
       "@type": "jsevent",
       ...
       "alerts": {
         "1": {

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           "@type": "Alert",
           "action": "display",
           "trigger": {
             "@type": "AbsoluteTrigger",
             "when": "19970317T133000Z"
           }
         },
         "2": {
           "@type": "Alert",
           "action": "display",
           "trigger": {
             "@type": "OffsetTrigger",
             "offset": "-PT30M"
           }
         }
         "3": {
           "@type": "Alert",
           "action": "email",
           "trigger": {
             "@type": "OffsetTrigger",
             "offset": "-P2D",
             "relativeTo": "end"
           }
         }
       }
     }

   Note that the ATTACH, ATTENDEE, DESCRIPTION, DURATION, REPEAT and
   SUMMARY properties have been dropped.

4.2.  VCALENDAR

   A [RFC5545] VCALENDAR component may be mapped to a JSCalendar object
   with a type of "jsgroup".

     BEGIN: VCALENDAR
     PRODID:-//ABC Corporation//NONSGML My Product//EN
     ...
     END: VCALENDAR

     maps to

     {
       "@type": "jsgroup",
       "prodid": "-//ABC Corporation//NONSGML My Product//EN",
       ...
     }

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   Note that a single JSEvent or JSTask MAY be converted without a
   surrounding JSGroup if the VCALENDAR component only contains PRODID
   and CALSCALE properties.  In this case the prddid can go in the
   JSEvent or JSTask.  The CALSCALE property is dropped - there is no
   equivalence in JSCalendar.

4.3.  VEVENT

   A [RFC5545] VEVENT component is mapped to a JSCalendar object with a
   type of "jsevent".

     BEGIN: VEVENT
     ...
     END: VEVENT

     maps to

     {
       "@type": "jsevent",
       ...
     }

4.4.  VLOCATION

   A [draft-ietf-calext-eventpub-extensions] VLOCATION component is
   mapped to a JSCalendar object with a type of "Location".  Any
   properties within the VLOCATION must be mapped as described below.

     BEGIN: VEVENT
     ...
     BEGIN: VLOCATION
     ...
     END: VLOCATION
     END: VEVENT

     maps to

     {
       "@type": "jsevent",
       ...
        "locations": {
          "1": {
            "@type": "Location",
            ...
          }
        }
     }

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4.5.  VTIMEZONE, STANDARD, DAYLIGHT

   A [RFC5545] VTIMEZONE component is mapped to a member of a JSCalendar
   "timezones" object with a type of "TimeZone" and an id which follows
   the restrictions specified.

   The STANDARD and DAYLIGHT components map to JSCalendar TimeZoneRule
   objects as members of the

   Note that

   o  There is no current approach for defining standalone sets of
      timezones.

   o  Timezones defined in the IANA timezone database SHOULD NOT be
      redefined in the object.  Only custom timezones will be defined.

     BEGIN: VTIMEZONE
     TZID: Example/Somewhere
     ...
     END: VTIMEZONE
     BEGIN: VTIMEZONE
     TZID: Example/Somewhere-else
     ...
     END: VTIMEZONE
     BEGIN: VEVENT
     ...
     END: VEVENT

     maps to

     {
       "@type": "jsevent",
       ...
       "timezones": {
         "/Example/Somewhere: {
           "@type": "TimeZone",
           ...
         },
         "/Example/Somewhere-else": {
           "@type": "TimeZone",
           ...
         }
       }
     }

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4.6.  VTODO

   A [RFC5545] VTODO component is mapped to a JSCalendar object with a
   type of "jstask".

     BEGIN: VTODO
     ...
     END: VTODO

     maps to

     {
       "@type": "jstask",
       ...
     }

5.  Translating iCalendar properties to JSCalendar

   This section is an alphabetic list of [RFC5545] and [RFC7986]
   properties and how they are mapped to JSCalendar.

5.1.  ATTACH

   A [RFC5545] ATTACH allows for two types of attachment:

   o  A uri value

   o  A binary value

   Both map to a JSCalendar "link" object with a "rel" of "enclosure"
   and the "href" set to the value of the property.

   If the FMTTYPE parameter is set then add a JSCalendar "contentType"
   property to the link object.

   For a binary value use a base64 data uri.

   For an example of a recurring event with ATTACH see Section 7.1

5.2.  ATTENDEE

   An [RFC5545] ATTENDEE maps to the JSCalendar "participant" property
   with a JSCalendar "role" of "attendee".  The value for role should
   always be set.

   In the simplest case a JSCalendar "participant" property will be
   created and added to the JSCalendar "participants" property.

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   The value of the ATTENDEE property is used to add an "imip" method to
   the JSCalendar "sendTo" property.  The value of the entry will be the
   ATTENDEE property value.

   For example:

     ...
     ATTENDEE:mailto:user01@example.org
     ...

     maps to

     {
     ...
         "participants": {
           "be450b70-9bf7-4f6e-8f65-971ede566ce3": {
             "@type": "Participant",
             "sendTo": {
               "imip": "user01@example.org"
             },
     ...
     }

   The attendee parameters are mapped to JSCalendar "participant"
   properties as follows:

   CN:  The value of the CN parameter is used to set the JSCalendar
      "name" property.

   CUTYPE:  This maps on to the JSCalendar "kind" property as follows:

      INDIVIDUAL  "individual"

      GROUP  "group"

      RESOURCE  "resource"

      ROOM  "location"

      UNKNOWN  No value

      Any other value should be converted to lower case and assigned to
      the JSCalendar "kind" property.

   DELEGATED-FROM:  Split the value at any commas and add each resulting
      element to the JSCalendar "delegatedFrom" property

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   DELEGATED-TO:  Split the value at any commas and add each resulting
      element to the JSCalendar "delegatedFrom" property

   DIR:  If non-null look in the participant "links" property for a
      JSCalendar "link" property with an href with the same value as the
      DIR parameter.  You may need to search the current override and
      the master.

      If none is found create a new one with the JSCalendar "href"
      property set to the value of the DIR parameter and the JSCalendar
      "rel" property set to "alternate"

   LANG:  set the JSCalendar "language" property to the value of the
      LANG parameter.

   MEMBER:  If this is set there should be a corresponding ATTENDEE
      object with a value equal to the value of the member parameter.
      If not it is appropriate to skip this parameter.

      If there is a corresponding ATTENDEE then there should be a
      corresponding JSCalendar "participant" property.  This suggests
      that CUTYPE=GROUP ATTENDEE properties should be processed ahead of
      the others.

      Locate the JSCalendar "participant" property for the group.  This
      may be in the current override or in the master.  Add the id to
      the current participants JSCalendar "memberOf" property.

   PARTSTAT:  If the PARTSTAT parameter is set and is not "NEEDS-ACTION"
      then set the JSCalendar "participationStatus" property to the
      lower-cased value of the PARTSTAT.

   ROLE:  This is mapped to the JSCalendar "roles" property as follows:

      CHAIR  "attendee" and "chair"

      REQ-PARTICIPANT  "attendee"

      OPT-PARTICIPANT  "attendee" and "optional"

      NON-PARTICIPANT  "informational"

      Any other value should be converted to lower case and added to the
      JSCalendar "roles" property.

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   RSVP:  If the value of the RSVP parameter is TRUE set the JSCalendar
      "expectReply" property to "true" otherwise omit it.

   SCHEDULE-AGENT:  If the value is "CLIENT" (ignoring case) set the
      JSCalendar "scheduleAgent" property to "client" otherwise omit it.

   SCHEDULE-FORCE-SEND:  Set the JSCalendar "scheduleForceSend" property
      to the lower-cased value of the [RFC6638] SCHEDULE-FORCE-SEND
      parameter.

   SCHEDULE-STATUS:  Split the value at any commas and add each
      resulting element to the JSCalendar "scheduleStatus" property.

   SENT-BY:  The value of the SENT-BY parameter is used to set the
      JSCalendar "invitedBy" property.

5.3.  CALSCALE

   A [RFC5545] CALSCALE has no equivalence in JSCalendar.  It is
   ignored.

5.4.  CATEGORIES

   These map on to the JSCalendar "keywords" property with each category
   being the key to an entry.

     ...
     CATEGORIES:APPOINTMENT,EDUCATION
     CATEGORIES:MEETING
     ...

     maps to

     ...
     "keywords": {
          "APPOINTMENT": true,
          "EDUCATION": true,
          "MEETING": true
        },
     ...

5.5.  CLASS

   Maps to the "privacy" property.  The iCalendar property value maps to
   the JSCalendar value as follows:

   CONFIDENTIAL  "secret"

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   PRIVATE  "private"

   PUBLIC  "public"

   iana-token and x-name  verbatim copy

5.6.  COLOR

   Maps to the "color" property.  Copy the verbatim value.

5.7.  COMMENT

   There is no direct mapping for this property which may appear
   multiple times in [RFC5545].

   For a scheduling reply it is presumably a message by the participant
   so the value or values should be used to set the JSCalendar
   "participantComment" property.

5.8.  COMPLETED

   Set the JSCalendar "progress" property to "completed" and the
   "progressUpdated" property to the reformatted date/time.

     ...
     COMPLETED: "20101010T101010Z"
     ...

     maps to

     ...
     "progressUpdated": "2010-10-10T10:10:10Z",
     "progress": "completed",
     ...

5.9.  CONCEPT

   This [draft-ietf-calext-ical-relations] property may appear multiple
   times in components.

   Each instance of the property is mapped on to a member of the
   JSCalendar "categories" property.

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     ...
     CONCEPT:http://example.com/event-types/arts/music
     CONCEPT:http://example.com/performance-types/arts/live
     ...

     maps to

     ...
     "categories": {
       "http://example.com/event-types/arts/music": true,
       "http://example.com/performance-types/arts/live": true
     }
     ...

5.10.  CONFERENCE

   Maps to a "VirtualLocation" object.  The property value maps to the
   "uri" property of the virtual location.

   Mapping parameters:

   FEATURE:  Maps to the "features" property of the virtual location.

   LABEL:  Maps to the "name" property of the virtual location.

   LANGUAGE:  No mapping.

5.11.  CONTACT

   The CONTACT property is mapped on to a participant object with a
   "roles" property of "contact" and an "order" property of 1 (one).
   This defines the participant as a primary contact.

   Mapping parameters:

   ALTREP  Use the same process as for the ATTENDEE DIR parameter:
      create a link property with the "rel" property set to "alternate"
      and the "href" property set to the value of the ALTREP parameter.
      Then add the link to the participants "links" property.

   LANG  Set the participants "language" property.

   For an example see Section 7.2

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5.12.  CREATED

   The CREATED property is mapped on to a "created" property with a json
   formatted form of the date.  Example:

     BEGIN:VEVENT
     ...
     CREATED:19960329T133000Z
     ...
     END:VEVENT

     maps to

     {
       "@type": "jsevent",
       ...
       "created": "1996-03-29T13:30"00Z",
       ...
     }

5.13.  DESCRIPTION

   Copy the value, preprocessed according to Section 3 into the
   "description" property.

   Mapping parameters:

   ALTREP  No mapping.

   LANG  Use the "locale" property.

   Example:

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     BEGIN:VEVENT
     ...
     DESCRIPTION:We are having a meeting all this week at 12 pm fo
      r one hour\, with an additional meeting on the first day 2 h
      ours long.\nPlease bring your own lunch for the 12 pm meetin
      gs.
     ...
     END:VEVENT

     maps to

     {
       "@type": "jsevent",
       ...
       "description": // Note: comments and string concatenation are not
               // allowed per the JSON specification and is used here
               // to avoid long lines.
           "We are having a meeting all this week at 12 pm for one " +
           "hour, with an additional meeting on the first day 2 " +
           "hours long.\nPlease bring your own lunch for the 12 pm " +
           "meetings.",
       ...
     }

5.14.  DTEND, DTSTART, DUE, DURATION

   If the DTSTART is a DATE only property then add the JSCalendar
   showWithoutTime property with the value set to "true".  The
   JSCalendar "start" property is set with zero time values.

   If the DTSTART has a TZID parameter then set the JSCalendar
   "timeZone" property to the value of TZID.

   If the DTSTART has a UTC value then set the JSCalendar "timeZone"
   property to the value "Etc/UTC".  The JSCalendar "start" property is
   set without any UTC indicator.

   JSCalendar has no equivalent to DTEND.  If the component has a DTEND
   then calculate a value for "DURATION" from that property and DTSTART
   and proceed as below.

   If the DTEND has a TZID parameter with a value that differs from the
   DTSTART TZID parameter then a "location" object should be created
   with a "relativeTo" property set to "end" and a "timezone" property
   set to the value of the "TZID" parameter.

   Note that a task is not required to have a DTSTART so the JSCalendar
   "timezone" property needs to be set from the DUE property.

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   Convert a DURATION property to the JSCalendar duration.

   Example - DTSTART and DTEND in same timezone:

     BEGIN:VEVENT
     ...
     DTSTART;TZID=America/New_York:20170315T150000
     DTEND;TZID=America/New_York:20170315T160000

     ...
     END:VEVENT

     maps to

     {
       "@type": "jsevent",
       ...
       "start": "2017-03-15T15:00:00",
       "timeZone": "America/New_York",
       "duration": "PT1H"
       ...
     }

   Example - DTSTART and DTEND in different timezone:

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     BEGIN:VEVENT
     ...
     DTSTART;TZID=America/New_York:20170315T150000
     DTEND;TZID=America/LosAngeles:20170315T190000

     ...
     END:VEVENT

     maps to

     {
       "@type": "jsevent",
       ...
       "start": "2017-03-15T15:00:00",
       "timeZone": "America/New_York",
       "duration": "PT7H"
       ...
       "locations": {
          "1": {
                 "@type": "location",
                 "relatedTo": "end",
                 "timeZone": "America/Los_Angeles"
               }
          }
     }

   Example - 3 day event:

     BEGIN:VEVENT
     ...
     DTSTART;VALUE=DATE:20210315
     DTEND;VALUE=DATE:20210318

     ...
     END:VEVENT

     maps to

     {
       "@type": "jsevent",
       ...
       "start": "2017-03-15T00:00:00",
       "duration": "P3D",
       "showWithoutTime": true,
       ...
     }

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5.15.  EXDATE

   Create a patch object with the recurrence id set from the EXDATE
   value.  Add a single JSCalendar "excluded" property with the value
   set to true.  There MUST NOT be any other properties set - other than
   "@type".

5.16.  EXRULE

   Maps to the "excludedRecurrenceRules" property.  Also see
   Section 5.31.

5.17.  DTSTAMP and LAST-MODIFIED

   The mapping depends on whether or not the component is a scheduling
   entity.

   Not a scheduling entity:  The [RFC5545] DTSTAMP and LAST-MODIFIED
      properties have essentially the same meaning.  If both are present
      use the value of the latest for the "updated" property.  Otherwise
      set from whichever is present.

   Is a scheduling entity:  DTSTAMP should be used to set the
      "ScheduleUpdated" property in the "participant" object for the
      attendee.

      If present LAST-MODIFIED should be used to set the "updated"
      property - otherwise set it from the DTSTAMP.

5.18.  GEO

   Maps to a Location object, with only the "coordinates" property set.
   Note that the JSCalendar coordinates property value MUST be a valid
   "geo" URI, so replace the ";" character in the iCalendar value with
   "," and prepend the resulting string with "geo:".

5.19.  IMAGE

   Maps to a Link object with the iCalendar property value mapped to the
   location "href" property, and the "rel" property set to "icon".

   For a binary value use a base64 data uri in the "href" property.

   Mapping parameters:

   ALTREP  No mapping.

   FMTTYPE  Maps to the "contentType" property of the Link object.

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   DISPLAY  Maps to the "display" property of the Link object.  The
      property values "BADGE", "GRAPHIC", "FULLSIZE" and "THUMBNAIL" map
      to their lower-case equivalent in JSCalendar.

5.20.  LOCATION

   If any [draft-ietf-calext-eventpub-extensions] "VLOCATION" components
   are present, then the [RFC5545]"LOCATION" property should be ignored.

   To map the property create a "locations" property with a single
   "location" and set the "description" property to the value of the
   [RFC5545]"LOCATION" property.

   Mapping parameters:

   ALTREP  Maps to a Link object in the Location "links" property, with
      the "href" property set to the parameter value.

5.21.  METHOD

   Maps to the "method" property of the JSCalendar object.  The
   JSCalendar property value is the lowercase equivalent of the
   iCalendar property value.

5.22.  ORGANIZER

   Maps to the "replyTo" property of the JSCalendar object.  An
   iCalendar property value in the "mailto:" URI scheme, maps to the
   "imip" method, any other value maps to the "other" method.

   If the iCalendar component also contains an ATTENDEE with the same
   calendar user address then map that ATTENDEE as defined in
   Section 5.2 and add the "owner" role to the Participant "roles"
   property.  Otherwise, use the ORGANIZER property to map to a
   Participant object.  The "roles" property of the Participant MUST
   only contain the "owner" role and the "expectReply" property value
   MUST be "false".  Any iCalendar parameters map as defined for
   ATTENDEE.

   TBD: SENT-BY parameter.  Example.

5.23.  PERCENT-COMPLETE

   For all methods other than REPLY (or no method), the PERCENT-COMPLETE
   applies to the VTODO as a whole.  In this case it the value is used
   to set the JSCalendar "percentComplete" property in the task object.

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     BEGIN: VCALENDAR
     PRODID:-//ABC Corporation//NONSGML My Product//EN
     METHOD:PUBLISH
     BEGIN:VTODO
     ...
     PERCENT-COMPLETE:39
     END:VTODO
     END: VCALENDAR

     maps to

     {
       "@type": "jstask",
       "prodid": "-//ABC Corporation//NONSGML My Product//EN",
       ...
       "percentComplete": 39
     }

   PERCENT-COMPLETE in a REPLY is used to indicate the level of
   completeness of the ATTENDEE.  There should only be a single ATTENDEE
   in the VTODO object.

   As ever recurrences complicate matters.  For a non-recurring event or
   an override that contains the single participant, set the JSCalendar
   "percentComplete" property in the JSCalendar "participant" object
   representing the attendee.

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     BEGIN: VCALENDAR
     PRODID:-//ABC Corporation//NONSGML My Product//EN
     METHOD:REPLY
     BEGIN:VTODO
     ...
     ATTENDEE:mailto:douglm@example.org
     PERCENT-COMPLETE:39
     END:VTODO
     END: VCALENDAR

     maps to

     {
       "@type": "jstask",
       "prodid": "-//ABC Corporation//NONSGML My Product//EN",
       ...
       "participants": {
         "be450b70-9bf7-4f6e-8f65-971ede566ce3": {
           "@type": "Participant",
           "sendTo": {
             "imip": "mailto:douglm@example.org"
           },
           "percentComplete": 39,
           "roles": {
             "attendee": true
           }
         },
         ...
     }

   In the case of an override with the participant appearing in the
   master then add a patch to the override.

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     BEGIN: VCALENDAR
     PRODID:-//ABC Corporation//NONSGML My Product//EN
     METHOD:REPLY
     BEGIN:VTODO
     ...
     ATTENDEE:mailto:douglm@example.org
     END:VTODO
     BEGIN:VTODO
     ...
     RECURRENCE-ID:20200523T120000
     ...
     ATTENDEE:mailto:douglm@example.org
     PERCENT-COMPLETE:39
     END:VTODO
     END: VCALENDAR

     maps to

     {
       "@type": "jstask",
       "prodid": "-//ABC Corporation//NONSGML My Product//EN",
       ...
       "participants": {
         "be450b70-9bf7-4f6e-8f65-971ede566ce3": {
           "@type": "Participant",
           "sendTo": {
             "imip": "mailto:douglm@example.org"
           },
           "roles": {
             "attendee": true
           }
         },
         "recurrenceOverrides": {
           "2020-05-23T12:00:00": {
             "participants/be4...6ce3/percentComplete": 39
           },
         ...
       }
     }

5.24.  PRIORITY

   Simply copy value into the JSCalendar "priority" property.

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5.25.  PRODID

   For a vcalendar JSGroup object with multiple JSEvent and/or JSTask
   object the [RFC5545] VCALENDAR PRODID is mapped to a JSCalendar
   "prodid" property in the group.

   When mapping to a single JSEvent and/or JSTask object the [RFC5545]
   VCALENDAR PRODID is mapped to a JSCalendar "prodid" property in the
   group

     BEGIN: VCALENDAR
     PRODID:-//ABC Corporation//NONSGML My Product//EN
     BEGIN:VEVENT
     ...
     END:VEVENT
     END: VCALENDAR

     maps to

     {
       "@type": "jsevent",
       "prodid": "-//ABC Corporation//NONSGML My Product//EN",
       ...
     }

5.26.  RECURRENCE-ID

   Refer to Section 6 for information on mapping recurrence ids.

5.27.  RELATED-TO

   This is mapped to the JSCalendar "relatedTo" property which is a map
   of relations with the target UID as the keys.  The iCalendar relation
   is by default a PARENT relationship.  There is no default for
   JSCalendar so the relationship must be explicitly specified.

   The RELTYPE parameter values map to their lowercase equivalents in
   the "relation" property.

   Also note that the iCalendar relationship types are not identical.
   CHILD and PARENT map to JSCalendar "child" and "parent" but the best
   match for iCalendar SIBLING is "next"

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     ...
     RELATED-TO:jsmith.part7.19960817T083000.xyzMail@example.com
     RELATED-TO;RELTYPE=SIBLING:
      19960401-080045-4000F192713-0052@example.com
     ...

     maps to

     "relatedTo" : {
       "jsmith.part7.19960817T083000.xyzMail@example.com" : {
         "@type" : "Relation",
         "relation" : {
           "parent" : true
         }
       },
       "19960401-080045-4000F192713-0052@example.com" : {
         "@type" : "Relation",
         "relation" : {
           "next" : true
         }
       },
     },
     {
       "@type": "jsevent",
       "prodid": "-//ABC Corporation//NONSGML My Product//EN",
       ...
     }

5.28.  REQUEST-STATUS

   Copy the value into the JSCalendar "requestStatus" property.

5.29.  RESOURCES

   The RESOURCES property value is a comma-separated list of resources.
   First split this into the separate resource names and then each
   resource is mapped on a participant object with a "kind" property of
   "resource" and the "name" property set to the resource name.

   Mapping parameters:

   ALTREP  Use the same process as for the ATTENDEE DIR parameter:
      create a link property with the "rel" property set to "alternate"
      and the "href" property set to the value of the ALTREP parameter.
      Then add the link to the participants "links" property.

   LANG  Set the participants "language" property.

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   For an example see Section 7.3

5.30.  RDATE

   If the RDATE has a RANGE=THISANDFUTURE parameter then the recurrence
   MUST be split at this RDATE.

   Truncate the original object before this RDATE, create a new master
   representing the object and link them by setting the jscalendar
   "relatedTo" property in both.

   Otherwise create a patch object with the recurrence id set from the
   RDATE value.  If the instance has overrides the differences will also
   be set in the object.

5.31.  RRULE

   Each RRULE is converted to an object in the JSCalendar
   "recurrenceRules" property.  Each entry has the type
   "RecurrenceRule".

     ...
     RRULE:...
     ...

     maps to

     ...
     "recurrenceRules" : [{
         "@type" : "RecurrenceRule",
         ...
       }],
       ...

   The recurrence rule object has one property for each element of the
   recurrence rule.  The iCalendar rule has to be parsed out and the
   individual jscalendar property values set.  Most take the same type
   but there are exceptions.

   FREQ (mandatory)  Copy into the jscalendar "frequency" property
      converted to lowercase.

   INTERVAL  If present and not 1 copy into the jscalendar "interval"
      property.

   RSCALE  If present copy into the jscalendar "rscale" property
      converted to lowercase.

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   SKIP  If present copy into the jscalendar "skip" property converted
      to lowercase.

   WKST  If present copy into the jscalendar "firstDayOfWeek" property
      converted to lowercase.

   BYDAY  If present each element becomes an entry in the jsCalendar
      "byDay" propety.  This is an array of NDay objects which may have
      2 properties:

      day  The two character weekday abbreviation.

      nthOfPeriod  If the weekday abbreviation is preceded by a signed
         integer value set the jscalendar "nthOfPeriod" property.

     ...
     RRULE:...,BYDAY=-1MO
     ...

     maps to

     ...
     "recurrenceRules" : [{
         "@type" : "RecurrenceRule",
         ...
         "byday": [{
             "day": "mo",
             "nthOfPeriod": -1
           }]
         ...
       }],
       ...

   BYMONTHDAY  If present each element will be an element in the
      jscalendar "byMonthDay" property.

   BYMONTH  If present each element will be an element in the jscalendar
      "byMonth" property.

      Note that the iCalendar values are numeric but the JSCalendar
      values are strings.  This is because of the possible "L" suffix
      for leap months.

   BYYEARDAY  If present each element will be an element in the
      jscalendar "byYearDay" property.

   BYWEEKNO  If present each element will be an element in the
      jscalendar "byWeekNo" property.

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   BYHOUR  If present each element will be an element in the jscalendar
      "byHour" property.

   BYMINUTE  If present each element will be an element in the
      jscalendar "byMinute" property.

   BYSECOND  If present each element will be an element in the
      jscalendar "bySecond" property.

   BYSETPOS  If present each element will be an element in the
      jscalendar "bySetPosition" property.

   COUNT  If present set in the jscalendar "count" property.

   UNTIL  If present set the jscalendar "until" property with the
      appropriately reformatted value.  If the is no time part append a
      0 time and reformat as a jscalendar local date/time.

   Some examples:

     ...
     RRULE:FREQ=DAILY;COUNT=10
     ...

     maps to

     ...
     "recurrenceRules" : [{
         "@type" : "RecurrenceRule",
         "frequency": "daily",
         "count": 10
       }],
       ...

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     ...
     RRULE:FREQ=YEARLY;UNTIL=20220512T140000Z;
      BYMONTH=1;BYDAY=SU,MO,TU,WE,TH,FR,SA
     ...

     maps to

     ...
     "recurrenceRules" : [{
         "@type" : "RecurrenceRule",
         "frequency": "yearly",
         "byMonth": ["1"],
         "byDay": [{
               "day": "su"
             },
             }
               "day": "mo"
             },
             }
               "day": "tu"
             },
             }
               "day": "we"
             },
             }
               "day": "th"
             },
             }
               "day": "fr"
             },
             }
               "day": "sa"
             }],
         "until": "2022-05-12T10:00:00"
       }],
       ...

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     ...
     RRULE:FREQ=MONTHLY;COUNT=6;BYDAY=-2MO
     ...

     maps to

     ...
     "recurrenceRules" : [{
         "@type" : "RecurrenceRule",
         "frequency": "monthly",
         "byDay": [{
             "day": "mo",
             "nthOfPeriod": -2
           }],
         "count": 6
       }],
       ...

5.32.  SEQUENCE

   Copy the value into the JSCalendar "sequence" property.

5.33.  STATUS

   For a VEVENT copy the lower-cased value into the JSCalendar "status"
   property.

   For a VTODO copy the lower-cased value into the JSCalendar "progress"
   property.

5.34.  STRUCTURED-DATA

   This property is mapped on to a JSCalendar "link" object with the
   value mapped on to the JSCalendar "href" property in a manner
   depending on the "STRUCTURED-DATA" "VALUE" parameter:

   VALUE=TEXT  Copy the value as a [RFC2397] data uri either as plain
      text or by encoding as a base64 value.  If plain text the value
      may need escaping as per [RFC2397].

   VALUE=BINARY  Copy the value as a [RFC2397] data uri speifying base64
      encoding.

   VALUE=URI  Copy the value as-is into the href.

   The "STRUCTURED-DATA" "SCHEMA" parameter is mapped on to a JSCalendar
   "schema" property within the link object.

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   The "STRUCTURED-DATA" "FMTTYPE" parameter is mapped on to a
   JSCalendar "contentType" property within the link object.

   For example:

     ...
     STRUCTURED-DATA;FMTTYPE=application/ld+json;
         SCHEMA="https://schema.org/SportsEvent";
         VALUE=TEXT:{\n
           "@context": "http://schema.org"\,\n
           "@type": "SportsEvent"\,\n
           "homeTeam": "Pittsburgh Pirates"\,\n
           "awayTeam": "San Francisco Giants"\n
         }\n
     ...

     maps to (with data truncated)

     ...
     "links": {
       "1": {
         "@type" : "Link",
         "contentType": "application/ld+json",
         "schema": "https://schema.org/SportsEvent",
         "href": "data:base64;ewogICAgICAgICJAY29udGV4dCI6IC..."
       }
     }
     ...

5.35.  SUMMARY

   Copy the value into the JSCalendar "title" property.

   Mapping parameters:

   ALTREP  No mapping.

   LANG  Use the "locale" property.

5.36.  TRANSP

   If the value of the TRANSP property (ignoring case) is "opaque" set
   the JSCalendar "freeBusyStatus" property to the value "busy".

   Otherwise set the JSCalendar "freeBusyStatus" property to the value
   "free".

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5.37.  UID

   Copy the value into the JSCalendar "uid" property.

5.38.  URL

   Maps to a Link object in the JSCalendar object's "links" property,
   with the URL property value mapped to the Link "href" property.

6.  Translating iCalendar Recurrences

6.1.  Translating iCalendar Recurrences: Simple objects with overrides

   A simple object with overrides will be converted to a jsCalendar
   master event with the rules, recurrence dates and exclusion dates
   translated appropriately.

   Overrides MUST be mapped on to a jsCalendar patch object and added to
   the "recurrenceOverrides" property of the master event with the key
   being the value of the iCalendar RECURRENCE-ID translated to a json
   format.

   Any override property with the same value as the master SHOULD be
   ommitted.  Remaining properties MAY be added in full.  Where
   appropriate, differences SHOULD be expressed as a patch.

   This can result in a significant reduction in size for objects with
   small changes to overrides, for example changing the participation
   status of an attendee.

6.2.  Translating iCalendar Recurrences: Overrides with no master

   When inviting an attendee to a single instance of a recurring event,
   only that override should be sent to the attendee.  In this case the
   override should be a complete jsCalendar object with the type set to
   the type of the master.

   Additionally, there MUST be a recurrenceId property set to the value
   of the recurrence id for that override.  If the timezone of the start
   of the instance is different from the master value, then there must
   also be a "recurrenceIdTimeZone" property set to the start timezone
   of the master.

7.  Translating iCalendar: Further examples

   This section provides more complete examples of translating from
   [RFC5545] to JSCalendar.

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   As usual note that json string values may be split because of line
   width limits.  This is not legal json.

7.1.  Recurring event with ATTACH

   This is an example of a recurring event with overrides.  The first
   override removes an ATTACH property and adds an ATTACH property.  The
   second override removes all ATTACH properties.

     BEGIN:VCALENDAR
     CALSCALE:GREGORIAN
     PRODID:-//example.org//EN
     VERSION:2.0
     BEGIN:VEVENT
     DTSTAMP:20200522T142047Z
     DTSTART;TZID=America/New_York:20200522T120000
     DURATION:PT1H
     RRULE:FREQ=DAILY;COUNT=8
     SUMMARY:recurring daily 8 times
     UID:6252D6C40A8308BFE25BBDErecur-1
     ATTACH;FMTTYPE=text/plain:http://example.org/doc1.txt
     ATTACH;FMTTYPE=text/plain:http://example.org/doc2.txt
     ATTACH;FMTTYPE=text/plain:http://example.org/doc3.txt
     END:VEVENT
     BEGIN:VEVENT
     DTSTAMP:20200522T142047Z
     DTSTART;TZID=America/New_York:20200523T120000
     DURATION:PT1H
     RECURRENCE-ID;TZID=America/New_York:20200523T120000
     SUMMARY:recurring daily 8 times
     UID:6252D6C40A8308BFE25BBDErecur-1
     ATTACH;FMTTYPE=text/plain:http://example.org/doc2.txt
     ATTACH;FMTTYPE=text/plain:http://example.org/doc3.txt
     ATTACH;FMTTYPE=text/plain:http://example.org/doc4.txt
     END:VEVENT
     BEGIN:VEVENT
     DTSTAMP:20200522T142047Z
     DTSTART;TZID=America/New_York:20200524T120000
     DURATION:PT1H
     RECURRENCE-ID;TZID=America/New_York:20200524T120000
     SUMMARY:recurring daily 8 times
     UID:6252D6C40A8308BFE25BBDErecur-1
     END:VEVENT
     END:VCALENDAR

     maps to

     {

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       "prodId": "//example.org//EN",
       "entries": [
         {
           "links": {
             "1": {
               "@type": "Link",
               "rel": "enclosure",
               "contentType": "text/plain",
               "href": "http://example.org/doc1.txt"
             },
             "2": {
               "@type": "Link",
               "rel": "enclosure",
               "contentType": "text/plain",
               "href": "http://example.org/doc2.txt"
             },
             "3": {
               "@type": "Link",
               "rel": "enclosure",
               "contentType": "text/plain",
               "href": "http://example.org/doc3.txt"
             }
           },
           "created ": "2020-05-23T17:04:50Z",
           "start": "2020-05-22T12:00:00",
           "timeZone": "America/New_York",
           "duration": "PT1H",
           "title": "recurring daily 8 times",
           "uid": "6252D6C40A8308BFE25BBDErecur-1",
           "recurrenceRules": [
             {
               "@type": "RecurrenceRule",
               "frequency": "daily",
               "count": 8
             }
           ],
           "recurrenceOverrides": {
             "2020-05-23T12:00:00": {
               "recurrenceId": "2020-05-23T12:00:00",
               "links/d4a618d4-929c-4c81-ae5b-322afe407a00": null,
               "links/fb75b76a-a159-4a86-bd3d-7ace6b39c6c3": {
                 "@type": "Link",
                 "rel": "enclosure",
                 "contentType": "text/plain",
                 "href": "http://example.org/doc4.txt"
               }
             },
             "2020-05-24T12:00:00": {

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               "recurrenceId": "2020-05-24T12:00:00",
               "links/d4a618d4-929c-4c81-ae5b-322afe407a00": null,
               "links/6c54e72e-3413-487c-ae14-fb318a90db43": null,
               "links/44087e9a-132c-4a5d-b25d-4ce580edb004": null
             }
           }
         }
       ]
     }

7.2.  Simple event with CONTACT

   This example shows the conversion of a simple event with a single
   CONTACT property in JSCalendar.

     BEGIN:VCALENDAR
     CALSCALE:GREGORIAN
     PRODID:-//Example//EN
     VERSION:2.0
     BEGIN:VEVENT
     DTSTAMP:20200522T142047Z
     DTSTART;TZID=America/New_York:20200622T120000
     DURATION:PT1H
     SUMMARY:event with contact
     UID:6252D6C40A8308BFE25BBEFcontact-1
     CONTACT;ALTREP="ldap://example.com:6666/o=ABC%20Industries\,
      c=US???(cn=Jim%20Dolittle)":Jim Dolittle\, ABC Industries\,
      +1-919-555-1234
     END:VEVENT
     END:VCALENDAR

     translates to

     {
       "@type": "jsgroup",
       "prodId": "//Example.org//Example V3.13.2//EN",
       "entries": [
         {
           "@type": "jsevent",
           "participants": {
             "40288108-733187c1-0173-3188007b-00000001": {
               "@type": "Participant",
               "roles": {
                 "contact": true
               },
               "description": "Jim Dolittle, ABC Industries,\
                              +1-919-555-1234",
               "links": {

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                 "1": {
                   "@type": "Link",
                   "href": "ldap://example.com:6666/o=ABC%20Industries,\
                                  c=US???(cn=Jim%20Dolittle)",
                   "rel": "alternate"
                 }
               }
             }
           },
           "created ": "2020-07-09T03:04:23Z",
           "start": "2020-06-22T12:00:00",
           "timeZone": "America/New_York",
           "duration": "PT1H",
           "title": "event with contact",
           "uid": "6252D6C40A8308BFE25BBEFcontact-1"
         }
       ]
     }

7.3.  Simple event with RESOURCES

   TBD

7.4.  Recurring event.  Attendees only in overrides

   In this more complex example there is no ORGANIZER or ATTENDEEs in
   the master event.  There are overrides which invite one or more
   attendees.

   For one overrride the ORGANIZER is also an ATTENDEE.  In the other
   that is not the case.  This is reflected in the "roles" property for
   the organizer.

   Note that each override has its own "participants" property and the
   first has a links property to handle the DIR parameter on one
   attendee.

       BEGIN:VCALENDAR
       PRODID://Example.org//Example V3.13.2//EN
       VERSION:2.0
       BEGIN:VEVENT
       CREATED:20200704T035515Z
       DURATION:PT1H
       DTSTAMP:20200704T035706Z
       DTSTART;TZID=America/New_York:20200522T120000
       LAST-MODIFIED:20200704T035706Z
       SUMMARY:recurring daily 8 times
       UID:6252D6C40A8308BFE25BBEFrecur1-1

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       RRULE:FREQ=DAILY;COUNT=8
       END:VEVENT
       BEGIN:VEVENT
       RECURRENCE-ID;TZID=America/New_York:20200523T120000
       ATTENDEE:mailto:douglm@example.org
       ATTENDEE;RSVP=TRUE;SCHEDULE-STATUS=1.2;DIR="http://example.org/
        vcards/vbede.vcf":mailto:vbede@example.org
       CREATED:20200704T035515Z
       DURATION:PT1H
       DTSTAMP:20200704T035706Z
       DTSTART;TZID=America/New_York:20200523T120000
       LAST-MODIFIED:20200704T035706Z
       ORGANIZER:mailto:douglm@example.org
       SUMMARY:recurring daily 8 times
       UID:6252D6C40A8308BFE25BBEFrecur1-1
       END:VEVENT
       BEGIN:VEVENT
       RECURRENCE-ID;TZID=America/New_York:20200524T120000
       ATTENDEE;RSVP=TRUE;SCHEDULE-STATUS=1.2:mailto:user01@example.org
       ATTENDEE;RSVP=TRUE;SCHEDULE-STATUS=1.2:mailto:vbede@example.org
       CREATED:20200704T035515Z
       DURATION:PT1H
       DTSTAMP:20200704T035706Z
       DTSTART;TZID=America/New_York:20200524T120000
       LAST-MODIFIED:20200704T035706Z
       ORGANIZER:mailto:douglm@example.org
       SUMMARY:recurring daily 8 times
       UID:6252D6C40A8308BFE25BBEFrecur1-1
       END:VEVENT
       END:VCALENDAR

       translates to

       {
         "@type": "jsgroup",
         "prodId": "//Example.org//Example V3.13.2//EN",
         "entries": [
           {
             "@type": "jsevent",
             "created ": "2020-07-04T03:57:06Z",
             "start": "2020-05-22T12:00:00",
             "timeZone": "America/New_York",
             "duration": "PT1H",
             "title": "recurring daily 8 times",
             "uid": "6252D6C40A8308BFE25BBEFrecur1-1",
             "recurrenceRules": [
               {
                 "@type": "RecurrenceRule",

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                 "frequency": "daily",
                 "count": 8
               }
             ],
             "recurrenceOverrides": {
               "2020-05-23T12:00:00": {
                 "participants": {
                   "be450b70-9bf7-4f6e-8f65-971ede566ce3": {
                     "@type": "Participant",
                     "sendTo": {
                       "imip": "mailto:douglm@example.org"
                     },
                     "roles": {
                       "attendee": true,
                       "owner": true
                     }
                   },
                   "a539dfe3-4463-4f28-b9de-17d3a0e99faf": {
                     "@type": "Participant",
                     "sendTo": {
                       "imip": "mailto:vbede@example.org"
                     },
                     "expectReply": true,
                     "links": {
                       "1": {
                         "@type": "Link",
                         "href": "http://example.org/vcards/vbede.vcf",
                         "rel": "alternate"
                       }
                     },
                     "roles": {
                       "attendee": true
                     },
                     "scheduleStatus": "1.2"
                   }
                 },
                 "replyTo": {
                   "imip": "mailto:douglm@example.org"
                 }
               },
               "2020-05-24T12:00:00": {
                 "participants": {
                   "daeae4cf-6f6a-4ce3-9f4d-6bd884650d3d": {
                     "@type": "Participant",
                     "sendTo": {
                       "imip": "mailto:user01@example.org"
                     },
                     "expectReply": true,

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                     "roles": {
                       "attendee": true
                     },
                     "scheduleStatus": "1.2"
                   },
                   "a6de6de3-271f-4679-9241-1b3bca6b602d": {
                     "@type": "Participant",
                     "sendTo": {
                       "imip": "mailto:vbede@example.org"
                     },
                     "expectReply": true,
                     "roles": {
                       "attendee": true
                     },
                     "scheduleStatus": "1.2"
                   },
                   "aaa8483b-b18b-4dbd-b218-77d8db027d35": {
                     "@type": "Participant",
                     "sendTo": {
                       "imip": "mailto:douglm@example.org"
                     },
                     "roles": {
                       "owner": true
                     }
                   }
                 },
                 "replyTo": {
                   "imip": "mailto:douglm@example.org"
                 }
               }
             }
           }
         ]
       }

8.  Security Considerations

   The same security considerations as for
   [draft-ietf-calext-jscalendar] apply.

9.  IANA Considerations

   None.

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10.  Acknowledgments

   The authors would like to thank the members of CalConnect for their
   valuable contributions.  This specification originated from the work
   of the API technical committee of CalConnect, the Calendaring and
   Scheduling Consortium.

11.  References

11.1.  Normative References

   [draft-ietf-calext-eventpub-extensions]
              "Event Publishing Extensions to iCalendar",
              <https://tools.ietf.org/html/draft-ietf-calext-eventpub-
              extensions>.

   [draft-ietf-calext-ical-relations]
              "Support for iCalendar Relationships",
              <https://tools.ietf.org/html/draft-ietf-calext-ical-
              relations>.

   [draft-ietf-calext-valarm-extensions]
              "VALARM Extensions for iCalendar",
              <https://tools.ietf.org/html/draft-ietf-calext-valarm-
              extensions>.

   [RFC2119]  Bradner, S., "Key words for use in RFCs to Indicate
              Requirement Levels", BCP 14, RFC 2119,
              DOI 10.17487/RFC2119, March 1997,
              <https://www.rfc-editor.org/info/rfc2119>.

   [RFC2397]  Masinter, L., "The "data" URL scheme", RFC 2397,
              DOI 10.17487/RFC2397, August 1998,
              <https://www.rfc-editor.org/info/rfc2397>.

   [RFC5545]  Desruisseaux, B., Ed., "Internet Calendaring and
              Scheduling Core Object Specification (iCalendar)",
              RFC 5545, DOI 10.17487/RFC5545, September 2009,
              <https://www.rfc-editor.org/info/rfc5545>.

   [RFC5546]  Daboo, C., Ed., "iCalendar Transport-Independent
              Interoperability Protocol (iTIP)", RFC 5546,
              DOI 10.17487/RFC5546, December 2009,
              <https://www.rfc-editor.org/info/rfc5546>.

   [RFC6638]  Daboo, C. and B. Desruisseaux, "Scheduling Extensions to
              CalDAV", RFC 6638, DOI 10.17487/RFC6638, June 2012,
              <https://www.rfc-editor.org/info/rfc6638>.

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   [RFC7159]  Bray, T., Ed., "The JavaScript Object Notation (JSON) Data
              Interchange Format", RFC 7159, DOI 10.17487/RFC7159, March
              2014, <https://www.rfc-editor.org/info/rfc7159>.

   [RFC7265]  Kewisch, P., Daboo, C., and M. Douglass, "jCal: The JSON
              Format for iCalendar", RFC 7265, DOI 10.17487/RFC7265, May
              2014, <https://www.rfc-editor.org/info/rfc7265>.

   [RFC7986]  Daboo, C., "New Properties for iCalendar", RFC 7986,
              DOI 10.17487/RFC7986, October 2016,
              <https://www.rfc-editor.org/info/rfc7986>.

11.2.  Informative References

   [draft-apthorp-ical-tasks]
              "Task Extensions to iCalendar",
              <https://tools.ietf.org/html/draft-apthorp-ical-tasks>.

   [draft-ietf-calext-jscalendar]
              "Task Extensions to iCalendar",
              <https://tools.ietf.org/html/draft-ietf-calext-
              jscalendar>.

Appendix A.  Outdated document sections

A.1.  Translating JSCalendar properties to iCalendar components

   This section is an alphabetic list of all JSCalendar property types
   that map on to components.

A.1.1.  jsevent

   A JSCalendar object with a type of "jsevent" is mapped on to a
   [RFC5545] VEVENT component.

   If it is a single VEVENT then a [RFC5545] VCALENDAR component must
   surround it and the JSCalendar "prodid" property will be converted to
   a [RFC5545] PRODID.

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     {
       "@type": "jsevent",
       "prodid": "-//ABC Corporation//NONSGML My Product//EN",
       ...
     }

     maps to

     BEGIN: VCALENDAR
     PRODID:-//ABC Corporation//NONSGML My Product//EN
     BEGIN:VEVENT
     ...
     END:VEVENT
     END: VCALENDAR

   When converting multiple JSEvent or JSTask objects the surrounding
   [RFC5545] VCALENDAR object must have a [RFC5545] PRODID set from
   either the JSGroup "prodid" or generated.

A.1.2.  jsgroup

   A JSCalendar object with a type of "jsgroup" is mapped on to a
   [RFC5545] VCALENDAR component.

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     {
       "@type": "jsgroup",
       "prodid": "-//ABC Corporation//NONSGML My Product//EN",
       ...
       {
         "@type": "jsevent",
         ...
       }
       {
         "@type": "jsevent",
         ...
       }
     }

     maps to

     BEGIN: VCALENDAR
     PRODID:-//ABC Corporation//NONSGML My Product//EN
     BEGIN:VEVENT
     ...
     END:VEVENT
     BEGIN:VEVENT
     ...
     END:VEVENT
     END: VCALENDAR

A.1.3.  jstask

   A JSCalendar object with a type of "jstask" is mapped on to a
   [RFC5545] VTODO component.

   If it is a single VTODO then a [RFC5545] VCALENDAR component must
   surround it and the JSCalendar "prodid" property will be converted to
   a [RFC5545] PRODID.

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     {
       "@type": "jstask",
       "prodid": "-//ABC Corporation//NONSGML My Product//EN",
       ...
     }

     maps to

     BEGIN: VCALENDAR
     PRODID:-//ABC Corporation//NONSGML My Product//EN
     BEGIN:VTODO
     ...
     END:VTODO
     END: VCALENDAR

   When converting multiple JSEvent or JSTask objects the surrounding
   [RFC5545] VCALENDAR object must have a [RFC5545] PRODID set from
   either the JSGroup "prodid" or generated.

A.1.4.  timezones

   The JSCalendar TimeZone objects within a "timezones" property are
   mapped on to [RFC5545] VTIMEZONE components within the surrounding
   VCALENDAR component.  Each mapped TimeZone MUST only appear once.

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     {
       "@type": "jsevent",
       ...
       "timezones": {
         "/Example/Somewhere: {
           "@type": "TimeZone",
           ...
         },
         "/Example/Somewhere-else": {
           "@type": "TimeZone",
           ...
         }
       }
     }

     maps to

     BEGIN: VTIMEZONE
     TZID: /Example/Somewhere
     ...
     END: VTIMEZONE
     BEGIN: VTIMEZONE
     TZID: /Example/Somewhere-else
     ...
     END: VTIMEZONE
     BEGIN: VEVENT
     ...
     END: VEVENT

   When converting multiple JSEvent or JSTask objects the surrounding
   [RFC5545] VCALENDAR object must have a [RFC5545] PRODID set from
   either the JSGroup "prodid" or generated.

A.1.5.  locations

   JSCalendar locations should be mapped on to
   [draft-ietf-calext-eventpub-extensions]VLOCATION components.
   Additionally, for backwards compatibility, a location should be
   mapped on to a [RFC5545] LOCATION property.  This property should be
   mapped from the only location or the one related to the start.

A.1.6.  participants

   JSCalendar participants will be mapped on to different iCalendar
   properties and components depending on their jsCalendar role values.

   A participant with a role containing "contact" MUST be mapped on to
   an iCalendar CONTACT property and SHOULD also be mapped on to a

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   [draft-ietf-calext-eventpub-extensions]PARTICIPANT component which
   provides a better mapping.

   A participant with a role containing "owner" MUST be mapped on to an
   iCalendar ORGANIZER property and SHOULD also be mapped on to a
   [draft-ietf-calext-eventpub-extensions]PARTICIPANT component which
   provides a better mapping.

   A participant with a role containing any of "attendee", "optional" or
   "informational" MUST be mapped on to an iCalendar ATTENDEE property
   and SHOULD also be mapped on to a
   [draft-ietf-calext-eventpub-extensions]PARTICIPANT component which
   provides a better mapping.

   A more complete mapping may be achieved by creating a
   [draft-ietf-calext-eventpub-extensions]PARTICIPANT component.

   For all properties the participants jsCalendar "language" property,
   if present, is mapped on to the iCalendar "LANG" property parameter.

   For all properties if the participant contains a jsCalendar "link"
   with a "rel" of "alternate" then the value of the link is used for
   the iCalendar "ALTREP" property parameter.

   Where do we get the cua?

A.2.  Note

   The sections following this one are all the original ones from draft
   1 writen by Robert/Neil - there for reference.

A.3.  JSEvent

   A JSEvent maps to the the iCalendar VEVENT component type [RFC5545].
   The following tables maps the JSEvent-specific properties to
   iCalendar:

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   +----------+--------------------------------------------------------+
   | Property | iCalendar counterpart                                  |
   +----------+--------------------------------------------------------+
   | duration | DURATION property.  If the VEVENT contains a DTEND     |
   |          | property, the this maps to the duration property as    |
   |          | the time span between DTSTART and DTEND when           |
   |          | converting the respective time points to the UTC time  |
   |          | zone.  Fractional seconds SHOULD be preserved with the |
   |          | SUBSECOND parameter.                                   |
   +----------+--------------------------------------------------------+

                    Table 1: Mapping JSEvent properties

A.4.  JSTask

   A JSTask object maps to the iCalendar VTODO component type [RFC5545].
   The following tables maps the JSTask-specific properties to
   iCalendar:

   +-------------------+-----------------------------------------------+
   | Property          | iCalendar counterpart                         |
   +-------------------+-----------------------------------------------+
   | due               | Maps to the DUE property. See Appendix A.6.1. |
   |                   |                                               |
   | estimatedDuration | ESTIMATED-DURATION property in the RFC draft  |
   |                   | [draft-apthorp-ical-tasks], or the DURATION   |
   |                   | property otherwise.  Fractional seconds       |
   |                   | SHOULD be preserved with the SUBSECOND        |
   |                   | parameter.                                    |
   |                   |                                               |
   | statusUpdatedAt   | COMPLETED property. The JSTask status         |
   |                   | property MUST have value "completed".         |
   |                   | Fractional seconds SHOULD be preserved with   |
   |                   | the SUBSECOND parameter.                      |
   |                   |                                               |
   | progress          | PARTSTAT and COMPLETED properties, including  |
   |                   | the definitions in the RFC draft              |
   |                   | [draft-apthorp-ical-tasks].                   |
   |                   |                                               |
   | status            | STATUS property, including the definitions in |
   |                   | the RFC draft [draft-apthorp-ical-tasks].     |
   +-------------------+-----------------------------------------------+

                    Table 2: Mapping JSTask properties

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A.5.  JSGroup

   A JSGroup maps to a iCalendar VCALENDAR containing VEVENT or VTODO
   components.

   +----------+--------------------------------------------------------+
   | Property | iCalendar counterpart                                  |
   +----------+--------------------------------------------------------+
   | entries  | VEVENT and VTODO components embedded in a VCALENDAR    |
   |          | component.                                             |
   |          |                                                        |
   | source   | SOURCE property.                                       |
   +----------+--------------------------------------------------------+

                    Table 3: Mapping JSGroup properties

A.6.  Common properties

   This section contains recommendations how to map JSCalendar from and
   to iCalendar.  It lists all common JSCalendar object properties in
   alphabetical order.

   +------------------------+------------------------------------------+
   | Property               | iCalendar counterpart                    |
   +------------------------+------------------------------------------+
   | @type                  | Determined by the iCalendar component    |
   |                        | type: "jsevent" for VEVENT, "jstask" for |
   |                        | VTODO, "jsgroup" for VCALENDAR.          |
   |                        |                                          |
   | alerts                 | Each entry maps to a VALARM component.   |
   |                        | The action property maps to iCalendar    |
   |                        | ACTION, where both iCalendar "DISPLAY"   |
   |                        | and "AUDIO" values map to the "display"  |
   |                        | action. An EMAIL value maps to a         |
   |                        | JSCalendar "email" action.  _relativeTo_ |
   |                        | and _offset_ map to the TRIGGER          |
   |                        | property.                                |
   |                        |                                          |
   | categories             | CONCEPT property, defined in             |
   |                        | [draft-ietf-calext-ical-relations].      |
   |                        |                                          |
   | color                  | COLOR property, as specified in          |
   |                        | [RFC7986].                               |
   |                        |                                          |
   | created                | CREATED property.  Fractional seconds    |
   |                        | SHOULD be preserved with the SUBSECOND   |
   |                        | parameter.                               |
   |                        |                                          |

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   | description            | DESCRIPTION property.                    |
   |                        |                                          |
   | descriptionContentType | Implementation-specific.                 |
   |                        |                                          |
   | excluded               | EXDATE property.  Fractional seconds     |
   |                        | SHOULD be preserved with the SUBSECOND   |
   |                        | parameter.                               |
   |                        |                                          |
   | freeBusyStatus         | TRANSP property.                         |
   |                        |                                          |
   | invitedBy              | Implementation-specific.                 |
   |                        |                                          |
   | keywords               | CATEGORIES property, as specified in     |
   |                        | [RFC7986].                               |
   |                        |                                          |
   | links                  | ATTACH ([RFC5545]), URL or IMAGE         |
   |                        | ([RFC7986]) properties with URI value    |
   |                        | types map to the the Link _href_.  The   |
   |                        | FMTTYPE parameter maps to _type_, the    |
   |                        | SIZE parameter to _size_.  Mapping other |
   |                        | properties is implementation-specific.   |
   |                        |                                          |
   | locale                 | LANGUAGE parameter of the SUMMARY or     |
   |                        | DESCRIPTION property.                    |
   |                        |                                          |
   | localizations          | Implementation-specific.                 |
   |                        |                                          |
   | locations              | See Appendix A.6.2.                      |
   |                        |                                          |
   | method                 | METHOD property of the embedding         |
   |                        | VCALENDAR.                               |
   |                        |                                          |
   | participants           | See Appendix A.6.3.                      |
   |                        |                                          |
   | priority               | PRIORITY property.                       |
   |                        |                                          |
   | privacy                | CLASS property.                          |
   |                        |                                          |
   | prodId                 | PRODID property.                         |
   |                        |                                          |
   | recurrenceOverrides    | RDATE and EXDATE properties, and any     |
   |                        | VEVENT or VTODO instances with a         |
   |                        | recurrence-id and same UID as the mapped |
   |                        | main object. If the DTSTART property     |
   |                        | defines a SUBSECOND parameter, but the   |
   |                        | RECURRENCE-ID of a recurrence instance   |
   |                        | does not, then use the SUBSECOND         |
   |                        | parameter value of DTSTART to determine  |

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   |                        | the recurrence override time stamp.      |
   |                        |                                          |
   | recurrenceRule         | RRULE property. For all-day calendar     |
   |                        | objects, map the _until_ property value  |
   |                        | to an iCalendar DATE (effectively        |
   |                        | removing the time component). To convert |
   |                        | a DATE-typed UNTIL from iCalendar, set   |
   |                        | the time components of the LocalDateTime |
   |                        | value to "23:59:59". If the iCalendar    |
   |                        | UNTIL value is a UTC date time, convert  |
   |                        | it to the local time in the JSCalendar   |
   |                        | calendar object time zone. To convert to |
   |                        | iCalendar where the DTSTART or DUE       |
   |                        | property is of type DATE, omit the time  |
   |                        | component of the LocalDateTime value.    |
   |                        |                                          |
   | relatedTo              | RELATED-TO property.                     |
   |                        |                                          |
   | replyTo                | An iCalendar ORGANIZER with a mailto:    |
   |                        | URI mapped to the "imip" method, or any  |
   |                        | other URI mapped to the "other" method.  |
   |                        | Mapping multiple methods is              |
   |                        | implementation-specific.                 |
   |                        |                                          |
   | sequence               | SEQUENCE property.                       |
   |                        |                                          |
   | showWithoutTime        | Implementation-specific.                 |
   |                        |                                          |
   | start                  | Maps to the DTSTART property. See        |
   |                        | Appendix A.6.1.                          |
   |                        |                                          |
   | status                 | STATUS property.                         |
   |                        |                                          |
   | timeZone               | Maps to the TZID parameter.  See         |
   |                        | Appendix A.6.1.                          |
   |                        |                                          |
   | timeZones              | Each entry in the property maps to a     |
   |                        | VTIMEZONE in the embedding VCALENDAR     |
   |                        | component.                               |
   |                        |                                          |
   | title                  | SUMMARY property.                        |
   |                        |                                          |
   | uid                    | UID property.                            |
   |                        |                                          |
   | updated                | DTSTAMP and LAST-MODIFIED properties.    |
   |                        | Fractional seconds SHOULD be preserved   |
   |                        | with the SUBSECOND parameter.            |
   |                        |                                          |

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   | useDefaultAlerts       | Implementation-specific.                 |
   |                        |                                          |
   | virtualLocations       | See Appendix A.6.2.                      |
   +------------------------+------------------------------------------+

           Table 4: Translation between JSCalendar and iCalendar

A.6.1.  Time properties and types

   iCalendar defines two different time types, DATE and DATE-TIME, where
   the latter may occur in three forms (with local time, with UTC time,
   with local time and time zone reference).  In contrast, JSCalendar
   does not define a distinct type for dates, and date times are defined
   with the LocalDateTime type only.

   A JSCalendar time maps to the iCalendar DATE type if all of the
   following criteria apply:

   o  The "start" ("due") property value has zero time, or is not set.

   o  The "duration" ("estimatedDuration") property value has zero time,
      or is a multiple of days or weeks, or is not set.

   o  The "timeZone" property value is null, or is not set.

   For all other cases, the time maps to an iCalendar DATE-TIME:

   o  With local time and time zone reference, if the "timeZone"
      property value is set and does not equal "Etc/UTC".

   o  With UTC time, if the "timeZone" property value equals "Etc/UTC".

   o  With local time, if the "timeZone" property value is null or not
      set.

   Fractional seconds SHOULD be preserved with the SUBSECOND parameter.

A.6.2.  Locations

   The iCalendar counterpart for JSCalendar Location objects is the
   iCalendar [RFC5545] LOCATION property, or implementation-specific.

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            +-------------+----------------------------------+
            | Property    | iCalendar counterpart            |
            +-------------+----------------------------------+
            | coordinates | GEO property.                    |
            |             |                                  |
            | description | Implementation-specific.         |
            |             |                                  |
            | name        | LOCATION property value.         |
            |             |                                  |
            | rel         | Implementation-specific.         |
            |             |                                  |
            | timeZone    | Implementation-specific.         |
            |             |                                  |
            | uri         | The LOCATION ALTREP parameter.   |
            +-------------+----------------------------------+

                   Table 5: Mapping Location properties

   The iCalendar counterpart for JSCalendar VirtualLocation objects is
   the iCalendar [RFC7986] CONFERENCE property.

              +-------------+------------------------------+
              | Property    | iCalendar counterpart        |
              +-------------+------------------------------+
              | description | Implementation-specific.     |
              |             |                              |
              | name        | LABEL parameter.             |
              |             |                              |
              | uri         | CONFERENCE property value.   |
              +-------------+------------------------------+

                Table 6: Mapping virtualLocation properties

A.6.3.  Participants

   The following table outlines translation of JSCalendar participants.
   An iCalendar ORGANIZER maps to both the replyTo property and a
   participant with role "owner".  If an ATTENDEE with the same CAL-
   ADDRESS value exists, then it maps to the same participant as the
   ORGANIZER participant.  Other participants map to ATTENDEEs.

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   +---------------------+---------------------------------------------+
   | Property            | iCalendar counterpart                       |
   +---------------------+---------------------------------------------+
   | attendance          | ROLE parameter values REQ-PARTICIPANT, OPT- |
   |                     | PARTICIPANT and NON-PARTICIPANT.            |
   |                     |                                             |
   | delegatedFrom       | DELEGATED-FROM parameter                    |
   |                     |                                             |
   | delegatedTo         | DELEGATED-TO parameter                      |
   |                     |                                             |
   | email               | EMAIL parameter, if defined. Otherwise the  |
   |                     | CAL-ADDRESS property value, if it is a      |
   |                     | mailto: URI.                                |
   |                     |                                             |
   | expectReply         | RSVP parameter                              |
   |                     |                                             |
   | kind                | CUTYPE parameter                            |
   |                     |                                             |
   | locationId          | Implementation-specific.                    |
   |                     |                                             |
   | memberOf            | MEMBER parameter                            |
   |                     |                                             |
   | name                | CN parameter                                |
   |                     |                                             |
   | participationStatus | PARTSTAT parameter                          |
   |                     |                                             |
   | roles               | ROLE parameter.                             |
   |                     |                                             |
   | scheduleSequence    | SEQUENCE property of the participant's      |
   |                     | latest iMIP message                         |
   |                     |                                             |
   | scheduleUpdated     | DTSTAMP property of the participant's       |
   |                     | latest iMIP message                         |
   |                     |                                             |
   | sendTo              | A CAL-ADDRESS with a mailto: URI maps to    |
   |                     | the JSCalendar "imip" method, any other URI |
   |                     | to the "other" method. Mapping multiple     |
   |                     | methods is implementation-specific.         |
   +---------------------+---------------------------------------------+

                  Table 7: Mapping Participant properties

A.7.  Custom properties

   Mapping custom or unknown properties between JSCalendar and iCalendar
   is implementation-specific.  Implementations might use vendor-
   extension properties, which could also serve as basis for discussion
   for a JSCalendar standard extension.  Alternatively, an

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   implementation could preserve iCalendar properties and components in
   JSCalendar by use of a vendor-extension property formatted as jCal
   [RFC7265] data.

Authors' Addresses

   Neil Jenkins
   FastMail
   PO Box 234
   Collins St West
   Melbourne  VIC 8007
   Australia

   Email: neilj@fastmailteam.com
   URI:   https://www.fastmail.com

   Robert Stepanek
   FastMail
   PO Box 234
   Collins St West
   Melbourne  VIC 8007
   Australia

   Email: rsto@fastmailteam.com
   URI:   https://www.fastmail.com

   Michael Douglass
   Bedework Commercial Services
   226 3rd Street
   Troy, NY  12180
   United States of America

   Email: mdouglass@bedework.com
   URI:   http://bedework.com

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