@fabio Nope.

Can it do:

export class Day extends CalendarUnit {
/** @type {Array<Slot>} */
slots = this.slots || new Array()
numberOfSlots = this.numberOfSlots || 4
slotDuration = this.slotDuration || 15 // minutes
persistedDate = this.persistedDate || Temporal.Now.zonedDateTimeISO().toJSON()
persistedStartTime = this.persistedStartTime || this.date.withPlainTime('13').toJSON()

// Automatic daily message flags.
sentMorningOfReminder = this.sentMorningOfReminder || false
sentDayBeforeReminder = this.sentDayBeforeReminder || false
sentWelcomeMessage = this.sentWelcomeMessage || false

initialise () {
this.slots ??=
[] this.numberOfSlots ??= 4
this.slotDuration ??= 15
if (this.slots.length === 0) {
for (let i = 0; i < this.numberOfSlots; i++) {
const slot = new Slot()
slot.dayId = this.id
this.addSlot(slot)
}
}
}

get date () {
return Temporal.ZonedDateTime.from(this.persistedDate)
}

set date (date) {
this.persistedDate = date.toJSON() || Temporal.Now.zonedDateTimeISO().toJSON()
}
…
}

kitten.db.calendar.addDay(new Day())

// ;)