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Function: mapErr()

mapErr<T, E1, E2>(result, fn): Result<T, E2>

Defined in: src/types/result.ts:288

Maps a function over the error of a Result.

Type Parameters​

• T

Success value type

• E1 extends Error

Original error type

• E2 extends Error

Transformed error type

Parameters​

result​

Result<T, E1>

Result to map over

fn​

(error) => E2

Error transformation function

Returns​

Result<T, E2>

New Result with transformed error, or original value

Remarks​

If the Result is Err, applies the function to the error and wraps the result in Err. If the Result is Ok, returns the value unchanged.

Useful for wrapping errors in more specific error types or adding context.

Example​

const result = Err(new Error('Failed'));
const wrapped = mapErr(result, (err) => new ValidationError(err.message));
// Err(ValidationError('Failed'))