mapOrNull<TResult extends Object?> method

  1. @optionalTypeArgs
TResult? mapOrNull<TResult extends Object?>({
  1. TResult? user(
    1. UserItem value
    )?,
  2. TResult? assistant(
    1. AssistantItem value
    )?,
  3. TResult? context(
    1. ContextItem value
    )?,
  4. TResult? historySummary(
    1. HistorySummaryItem value
    )?,
})

A variant of map that fallback to returning null.

It is equivalent to doing:

switch (sealedClass) {
  case final Subclass value:
    return ...;
  case _:
    return null;
}

Implementation

@optionalTypeArgs TResult? mapOrNull<TResult extends Object?>({TResult? Function( UserItem value)?  user,TResult? Function( AssistantItem value)?  assistant,TResult? Function( ContextItem value)?  context,TResult? Function( HistorySummaryItem value)?  historySummary,}){
final _that = this;
switch (_that) {
case UserItem() when user != null:
return user(_that);case AssistantItem() when assistant != null:
return assistant(_that);case ContextItem() when context != null:
return context(_that);case HistorySummaryItem() when historySummary != null:
return historySummary(_that);case _:
  return null;

}
}