whenOrNull<TResult extends Object?> method

@optionalTypeArgs TResult? whenOrNull<TResult extends Object?>(TResult? $default(String? password, @JsonKey.new(name: 'ascii') String? ascii, String? customTable, @JsonKey.new(name: 'custom_table') String? legacyCustomTable, List<String>? customTables, @JsonKey.new(name: 'custom_tables') List<String>? legacyCustomSets, int? paddingMin, @JsonKey.new(name: 'padding_min') int? legacyPaddingMin, int? paddingMax, @JsonKey.new(name: 'padding_max') int? legacyPaddingMax,)?)

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? password,
          @JsonKey(name: 'ascii') String? ascii,
          String? customTable,
          @JsonKey(name: 'custom_table') String? legacyCustomTable,
          List<String>? customTables,
          @JsonKey(name: 'custom_tables') List<String>? legacyCustomSets,
          int? paddingMin,
          @JsonKey(name: 'padding_min') int? legacyPaddingMin,
          int? paddingMax,
          @JsonKey(name: 'padding_max') int? legacyPaddingMax)?
      $default,
) {
  final _that = this;
  switch (_that) {
    case _Sudoku() when $default != null:
      return $default(
          _that.password,
          _that.ascii,
          _that.customTable,
          _that.legacyCustomTable,
          _that.customTables,
          _that.legacyCustomSets,
          _that.paddingMin,
          _that.legacyPaddingMin,
          _that.paddingMax,
          _that.legacyPaddingMax);
    case _:
      return null;
  }
}