# Function: isFailure()

> **isFailure**\<`R`>(`result`): `result is Extract<R, { type: "Failure" }>`

Type guard to check if a [Result](../types/Result.Result.md) is a [Failure](../types/Result.Failure.md).

## Type Parameters

### R

`R` _extends_ [`Result`](../types/Result.Result.md)\<`unknown`, `unknown`>

The type of the result to check.

## Parameters

### result

`R`

The [Result](../types/Result.Result.md) to check.

## Returns

`result is Extract<R, { type: "Failure" }>`

`true` if the result is a [Failure](../types/Result.Failure.md), otherwise `false`.

## Example

```ts
import { Result } from '@praha/byethrow';

const result: Result.Result<number, string> = { type: 'Failure', error: 'Something went wrong' };
if (Result.isFailure(result)) {
  console.error(result.error); // Safe access to error
}
```