mapErr<F extends Object> method

Result<T, F> mapErr<F extends Object>(F block(E error))

Transforms the error value using block, leaving success values unchanged.

If this is Err, applies block to the error and wraps the result in a new error type. If this is Ok, returns the same success value with the new error type. Useful for converting error types when delegating to functions expecting different error types.

Example:

Result<String, String> result = Err('failed');
final mapped = result.mapErr((e) => CustomError(e)); // Err(CustomError)

Implementation

Result<T, F> mapErr<F extends Object>(F Function(E error) block) =>
    switch (this) {
      Err<T, E>(:final error, :final stackTrace) => .err(
        block(error),
        stackTrace,
      ),
      Ok<T, E>(:final value) => .ok(value),
    };