How to code universal converter for typed objects

[iBobik]

Hello,
I migrate existing project where I used pinia-firestore and typed class objects. I want to have all documents in Firestore typed, so I need FirestoreDataConverter to wire types properly.

Currently I use custom converters like this:

const EventScheduleConverter: FirestoreDataConverter<EventScheduleItem> = {
  toFirestore(item: EventScheduleItem): any {
    const data: any = { ...item }
    data.blocks = item.blocks.map(block => ({ ...block }))
    data.time.start = Timestamp.fromDate(item.time.start)
    if (item.time.originalStart) data.time.originalStart = Timestamp.fromDate(item.time.originalStart)
    if (item.time.duration) data.time.duration = item.time.duration
    return data
  },

  fromFirestore(snapshot: QueryDocumentSnapshot, options: SnapshotOptions): EventScheduleItem {
    const data = snapshot.data(options)
    data.time.start = data.time.start.toDate()
    if (data.time.originalStart) data.time.originalStart = data.time.originalStart.toDate()
    return Object.assign(new EventScheduleItem(), data)
  }
}

const EventPerformersConverter: FirestoreDataConverter<EventPerformer> = {
  toFirestore(item: EventPerformer): any {
    const data: any = { ...item }
    return data
  },

  fromFirestore(snapshot: QueryDocumentSnapshot, options: SnapshotOptions): EventPerformer {
    const data = snapshot.data(options)
    return Object.assign(new EventPerformer(), data)
  }
}

Most important part is to pack and unpack class because Firebase wants generic objects. Secondly it converts Timestamps to Dates and vice-versa. Possibly other types will be added when needed.

I want to replace this custom converters by a generic converter what will do it all automatically. I can imagine what to do with Timestamps etc, but I am lost about typings - to use one converter but collections and docs will be properly typed. I does not necessarily need to use classes (I use them only for initialising default values).

Is it possible?
Do you have some working examples?

[iBobik]

I would use also some more docs on how to properly work with types. E.g. in a custom converter it complains about optional id (because class could be new):