when<TResult extends Object?> method

@optionalTypeArgs TResult when<TResult extends Object?>({ required TResult user(String id, String chatId, String userId, DateTime timestamp, String text,), required TResult assistant(String id, String chatId, String userId, DateTime timestamp, String? modelId, String text,), required TResult context(String id, String chatId, String userId, DateTime timestamp, String text,), required TResult historySummary(String id, String chatId, String userId, DateTime timestampFrom, DateTime timestamp, String? modelId, String text,), })

A switch-like method, using callbacks.

As opposed to map, this offers destructuring. It is equivalent to doing:

switch (sealedClass) {
  case Subclass(:final field):
    return ...;
  case Subclass2(:final field2):
    return ...;
}

Implementation

@optionalTypeArgs TResult when<TResult extends Object?>({required TResult Function( String id,  String chatId,  String userId,  DateTime timestamp,  String text)  user,required TResult Function( String id,  String chatId,  String userId,  DateTime timestamp,  String? modelId,  String text)  assistant,required TResult Function( String id,  String chatId,  String userId,  DateTime timestamp,  String text)  context,required TResult Function( String id,  String chatId,  String userId,  DateTime timestampFrom,  DateTime timestamp,  String? modelId,  String text)  historySummary,}) {final _that = this;
switch (_that) {
case UserItem():
return user(_that.id,_that.chatId,_that.userId,_that.timestamp,_that.text);case AssistantItem():
return assistant(_that.id,_that.chatId,_that.userId,_that.timestamp,_that.modelId,_that.text);case ContextItem():
return context(_that.id,_that.chatId,_that.userId,_that.timestamp,_that.text);case HistorySummaryItem():
return historySummary(_that.id,_that.chatId,_that.userId,_that.timestampFrom,_that.timestamp,_that.modelId,_that.text);}
}