Calendar plugin for Cordova already exist. It support iOS and Android platforms and could be easily extended to support both WP8 and Windows 8
- listCalendars/createCalendar/deleteCalendar
- getCalendarOptions/getCreateCalendarOptions
- createEvent/createEventWithOptions/createEventInteractively/createEventInNamedCalendar
- modifyEvent/modifyEventInNamedCalendar
- deleteEvent/deleteEventFromNamedCalendar
- findEvent/findAllEventsInNamedCalendar
- listEventsInRange
Windows.ApplicationModel.Appointments classes from Windows store API provides almost the same functionality.
Also Windows API has another methods' names, e.g.:
- DeleteAppointmentAsync instead of deleteEvent
- ShowEditNewAppointmentAsync instead of createEventInteractively
etc.
- WP8: read-only access to calendar and appointment data (http://goo.gl/RFYruF)
- WP 8.1: read/write access to calendar and appointment data. Almost full Calendar plugin API support
- Windows8: no api available (api exists starting from 8.1)
- Windows8.1: appointments only (no managing calendars support) in interactive mode (plugin will show Calendar App popup with appointment details and Add/Save/Delete button)
Raw ETA for implementing calendar API ~ 1-1.5 week