Multi-value property support (ATTENDEE, CATEGORIES)

[PhilflowIO]

Problem

Properties like ATTENDEE and CATEGORIES can have multiple values, but current implementation only handles single string values.

Example

BEGIN:VEVENT
ATTENDEE;CN=Alice:mailto:alice@example.com
ATTENDEE;CN=Bob:mailto:bob@example.com
ATTENDEE;CN=Charlie:mailto:charlie@example.com
CATEGORIES:MEETING,WORK,IMPORTANT
END:VEVENT

Current Behavior

// Only updates the first ATTENDEE
updateFields(event, {
  'ATTENDEE': 'mailto:newperson@example.com'
});

Desired Behavior

// Support array of values
updateFields(event, {
  'ATTENDEE': [
    'mailto:alice@example.com',
    'mailto:bob@example.com'
  ],
  'CATEGORIES': ['MEETING', 'WORK']
});

Implementation Considerations

• Need to detect multi-value properties
• Handle both single string and array inputs
• Preserve property parameters (CN, ROLE, etc. for ATTENDEE)
• Stay true to field-agnostic philosophy

Workaround

Use ical.js directly for multi-value properties:

import ICAL from 'ical.js';

const component = new ICAL.Component(ICAL.parse(event.data));
const vevent = component.getFirstSubcomponent('vevent');

// Add multiple attendees
const attendees = [
  'mailto:alice@example.com',
  'mailto:bob@example.com'
];

// Remove existing
vevent.removeAllProperties('attendee');

// Add new ones
attendees.forEach(email => {
  vevent.addPropertyWithValue('attendee', email);
});

// Use tsdav-utils for other fields
const updated = updateFields(component.toString(), {
  'SUMMARY': 'Team Meeting'
});

Related

• RFC 5545 Section 3.8.4.1 (ATTENDEE)
• RFC 5545 Section 3.8.1.2 (CATEGORIES)