whenOrNull<TResult extends Object?> method

@optionalTypeArgs TResult? whenOrNull<TResult extends Object?>(TResult? $default(String? description, String? name, PPAmount? unitPrice, int? quantity, PPAmount? total, dynamic details,)?)

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(String? description, String? name, PPAmount? unitPrice,
          int? quantity, PPAmount? total, dynamic details)?
      $default,
) {
  final _that = this;
  switch (_that) {
    case _PPItem() when $default != null:
      return $default(_that.description, _that.name, _that.unitPrice,
          _that.quantity, _that.total, _that.details);
    case _:
      return null;
  }
}