# either Functions

Consider the following code for the examples below

```fsharp
// int -> int
let okF (x : int) = x + 1

// int -> int
let errorF (x : int) = x - 1
```

## Result.either

Namespace: `FsToolkit.ErrorHandling`

If the result is ok, perform a function on the ok value which returns a value. If the result is an error, perform a function on the error value which returns a value.

### Function Signature

```fsharp
('okInput -> 'output) -> ('errorInput -> 'output) 
    -> Result<'okInput, 'errorInput> -> 'output
```

### Examples

#### Example 1

```fsharp
let result =
    Ok 1
    |> Result.either okF errorF
    
// 2
```

## Result.eitherMap

Namespace: `FsToolkit.ErrorHandling`

If the result is ok, perform a function on the ok value to map it to another result type. If the result is an error, perform a function on the error value to map it to another result type.

### Function Signature

```fsharp
('okInput -> 'okOutput) -> ('errorInput -> 'errorOutput) -> Result<'okInput, 'errorInput> 
    -> Result<'okOutput, 'errorOutput>
```

### Examples

#### Example 1

```fsharp
let result =
    Error 1
    |> Result.eitherMap okF errorF
    
// 0
```


---

# Agent Instructions: Querying This Documentation

If you need additional information that is not directly available in this page, you can query the documentation dynamically by asking a question.

Perform an HTTP GET request on the current page URL with the `ask` query parameter:

```
GET https://demystifyfp.gitbook.io/fstoolkit-errorhandling/fstoolkit.errorhandling/result/eitherfunctions.md?ask=<question>
```

The question should be specific, self-contained, and written in natural language.
The response will contain a direct answer to the question and relevant excerpts and sources from the documentation.

Use this mechanism when the answer is not explicitly present in the current page, you need clarification or additional context, or you want to retrieve related documentation sections.