FullCalendar Interop

Interop boundary

The plugin runtime uses internal OFCEvent objects, while the view layer uses FullCalendar event primitives. core/interop.ts is the translation boundary between those two worlds.

Why interop is independent core logic

Interop is not UI glue; it is a correctness boundary. It controls how recurrence, all-day semantics, category presentation, and timezone-aware fields are represented when crossing between internal state and FullCalendar runtime APIs.

Core conversion paths

Direction	Function	Purpose
Internal -> FullCalendar	toEventInput	Converts canonical event state into renderable FullCalendar input, including recurrence and display properties.
FullCalendar drag/resize -> internal	dateEndpointsToFrontmatter and related helpers	Converts user-edited date endpoints into internal event shape fields for cache mutation.

Recurrence and timezone handling in interop

Interop logic builds recurrence payloads and validates recurrence shape before rendering. Time values are parsed/combined carefully so edited event endpoints return deterministic internal fields instead of UI-library-specific artifacts.

Category and display mapping

When advanced categorization is enabled, interop maps category/subcategory display, color resources, and timeline resource IDs so the visual model stays aligned with normalized event metadata.

Contract

Interop should never become a second source of truth. It translates representations; ownership of event state and mutation policy remains in EventCache.

Integration anchors

• src/core/interop.ts
• src/ui/view.ts
• src/core/EventCache.ts