mapErr<F> method
Transforms the contained error, if any, by applying map
to it.
Examples
// prints "Ok(2)"
print(const Ok<int, String>(2).mapErr((error) => '$error!'));
// prints "Err(error!)"
print(const Err<int, String>('error').mapErr((error) => '$error!'));
Implementation
@override
@useResult
Err<T, F> mapErr<F>(F Function(E error) map) => Err(map(error));