whenOrNull<TResult extends Object?> method

@optionalTypeArgs TResult? whenOrNull<TResult extends Object?>(TResult? $default(String? host, String? path, Map<String, String>? headers, bool? acceptProxyProtocol, int? heartbeatPeriod,)?)

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? host, String? path, Map<String, String>? headers,
          bool? acceptProxyProtocol, int? heartbeatPeriod)?
      $default,
) {
  final _that = this;
  switch (_that) {
    case _WebSocketConfig() when $default != null:
      return $default(_that.host, _that.path, _that.headers,
          _that.acceptProxyProtocol, _that.heartbeatPeriod);
    case _:
      return null;
  }
}