silverbullet-icalendar/conductor/tracks/fix_rrule_object_mapping_20260219/spec.md

Specification: Fix RRULE Object Expansion Error

Overview

The previous fix for handling object-type rrule properties (returned by ts-ics) introduced a regression. The conversion logic used uppercase full names (e.g., FREQUENCY), but the rrule library's parseString method expects standard iCalendar shortened keys (e.g., FREQ). This results in an Error: Unknown RRULE property 'FREQUENCY'.

Functional Requirements

• Correct Key Mapping: The logic that converts an rrule object back to a string must use standard iCalendar RRULE property keys.
• Mapping Table:
  • frequency -> FREQ
  • until -> UNTIL
  • count -> COUNT
  • interval -> INTERVAL
  • bysecond -> BYSECOND
  • byminute -> BYMINUTE
  • byhour -> BYHOUR
  • byday -> BYDAY
  • bymonthday -> BYMONTHDAY
  • byyearday -> BYYEARDAY
  • byweekno -> BYWEEKNO
  • bymonth -> BYMONTH
  • bysetpos -> BYSETPOS
  • wkst -> WKST
• Case Insensitivity: The mapping should be case-insensitive for the input object keys.

Implementation Steps

1. Reproduce: Update the existing expandRecurrences - object rrule test case to use the key frequency and verify it fails with the reported error.
2. Fix: Implement a mapping function in icalendar.ts to translate object keys to standard RRULE keys before stringifying.
3. Verify: Run the test case to confirm it now passes.

Acceptance Criteria

• Test expandRecurrences - object rrule passes with an object using frequency key.
• No "Unknown RRULE property" errors are logged for valid RRULE objects.