when<TResult extends Object?> method

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

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?>(
  TResult Function(String? description, String? name, PPAmount? unitPrice,
          int? quantity, PPAmount? total, dynamic details)
      $default,
) {
  final _that = this;
  switch (_that) {
    case _PPItem():
      return $default(_that.description, _that.name, _that.unitPrice,
          _that.quantity, _that.total, _that.details);
    case _:
      throw StateError('Unexpected subclass');
  }
}