maybeWhen<TResult extends Object?> method

  1. @optionalTypeArgs
TResult maybeWhen<TResult extends Object?>(
  1. TResult $default(
    1. String op,
    2. List<CustomTransformArg> args
    )?, {
  2. required TResult orElse(),
})

A variant of when that fallback to an orElse callback.

It is equivalent to doing:

switch (sealedClass) {
  case Subclass(:final field):
    return ...;
  case _:
    return orElse();
}

Implementation

@optionalTypeArgs
TResult maybeWhen<TResult extends Object?>(
  TResult Function(String op, List<CustomTransformArg> args)? $default, {
  required TResult orElse(),
}) {
  final _that = this;
  switch (_that) {
    case _CustomTransform() when $default != null:
      return $default(_that.op, _that.args);
    case _:
      return orElse();
  }
}