method Result.prototype.mapErr
Result.prototype.mapErr<F extends BaseError>(fn: (error: E) => F): Result<T, F>

Transforms the Err value using a mapper function, leaving Ok untouched.

Examples

Example 1

const result = Result.err(new ValidationError("Failed"))
  .mapErr(e => new NetworkError({ cause: e }));

Type Parameters

F extends BaseError

The type of the transformed error

Parameters

fn: (error: E) => F

Function to transform the Err value

Return Type

A new Result with the transformed error, or the original Ok

Usage

import { Result } from "result/mod.ts";