when<TResult extends Object?> method

@optionalTypeArgs TResult when<TResult extends Object?>(TResult $default(String? currencyFormat, String? currencyFormatSymbolISOCurrency, String? currencyCode, String? currencySymbol, String? currencyValue,))

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? currencyFormat,
          String? currencyFormatSymbolISOCurrency,
          String? currencyCode,
          String? currencySymbol,
          String? currencyValue)
      $default,
) {
  final _that = this;
  switch (_that) {
    case _Amount():
      return $default(
          _that.currencyFormat,
          _that.currencyFormatSymbolISOCurrency,
          _that.currencyCode,
          _that.currencySymbol,
          _that.currencyValue);
    case _:
      throw StateError('Unexpected subclass');
  }
}