whenOrNull<TResult extends Object?> method

  1. @optionalTypeArgs
TResult? whenOrNull<TResult extends Object?>({
  1. TResult? threadItemPost(
    1. ThreadItemPost data
    )?,
  2. TResult? threadItemNoUnauthenticated(
    1. ThreadItemNoUnauthenticated data
    )?,
  3. TResult? threadItemNotFound(
    1. ThreadItemNotFound data
    )?,
  4. TResult? threadItemBlocked(
    1. ThreadItemBlocked data
    )?,
  5. TResult? unknown(
    1. Map<String, dynamic> data
    )?,
})

A variant of when that fallback to returning null

It is equivalent to doing:

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

Implementation

@optionalTypeArgs TResult? whenOrNull<TResult extends Object?>({TResult? Function( ThreadItemPost data)?  threadItemPost,TResult? Function( ThreadItemNoUnauthenticated data)?  threadItemNoUnauthenticated,TResult? Function( ThreadItemNotFound data)?  threadItemNotFound,TResult? Function( ThreadItemBlocked data)?  threadItemBlocked,TResult? Function( Map<String, dynamic> data)?  unknown,}) {final _that = this;
switch (_that) {
case UThreadItemValueThreadItemPost() when threadItemPost != null:
return threadItemPost(_that.data);case UThreadItemValueThreadItemNoUnauthenticated() when threadItemNoUnauthenticated != null:
return threadItemNoUnauthenticated(_that.data);case UThreadItemValueThreadItemNotFound() when threadItemNotFound != null:
return threadItemNotFound(_that.data);case UThreadItemValueThreadItemBlocked() when threadItemBlocked != null:
return threadItemBlocked(_that.data);case UThreadItemValueUnknown() when unknown != null:
return unknown(_that.data);case _:
  return null;

}
}