Function mapErr

mapErr<T, E, F>(result: Result<T, E>, fn: (error: E) => F): Result<T, F>
Transform the Err value, passing Ok through unchanged. Useful for unifying heterogeneous failure types into one app-level union.
Type Parameters
- T
- E
- F
Parameters
- result: Result<T, E>
- fn: (error: E) => F
Returns Result<T, F>
Example
```
type AppError = { kind: "http"; status: number } | { kind: "parse" };
pipe(
  fetchSync(url),                                     // Result<Body, { status: number }>
  mapErr((e): AppError => ({ kind: "http", status: e.status })),
);
```
- Defined in packages/result/src/result.ts:106
mapErr<E, F>(fn: (error: E) => F): <T>(result: Result<T, E>) => Result<T, F>
Transform the Err value, passing Ok through unchanged. Useful for unifying heterogeneous failure types into one app-level union.
Type Parameters
- E
- F
Parameters
- fn: (error: E) => F
Returns <T>(result: Result<T, E>) => Result<T, F>
Example
```
type AppError = { kind: "http"; status: number } | { kind: "parse" };
pipe(
  fetchSync(url),                                     // Result<Body, { status: number }>
  mapErr((e): AppError => ({ kind: "http", status: e.status })),
);
```
- Defined in packages/result/src/result.ts:107