when<TResult extends Object?> method

@optionalTypeArgs TResult when<TResult extends Object?>({ required TResult network(String url, ImageParams params), required TResult base64(String base64Code, ImageParams params), required TResult filePath(String filePath, ImageParams params), required TResult asset(String assetPath, ImageParams params), })

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?>({
  required TResult Function(String url, ImageParams params) network,
  required TResult Function(String base64Code, ImageParams params) base64,
  required TResult Function(String filePath, ImageParams params) filePath,
  required TResult Function(String assetPath, ImageParams params) asset,
}) {
  final _that = this;
  switch (_that) {
    case MyNetworkImage():
      return network(_that.url, _that.params);
    case MyBase64Image():
      return base64(_that.base64Code, _that.params);
    case MyFilePathImage():
      return filePath(_that.filePath, _that.params);
    case MyAssetImage():
      return asset(_that.assetPath, _that.params);
  }
}