---
url: >-
  https://lit-ui-router.dev/api/ui-router-server/prerender/type-aliases/FileWriter.md
---
[ui-router-server](../../index.md) / [prerender](../index.md) / FileWriter

# Type Alias: FileWriter

```ts
type FileWriter = (file, body) => void | Promise<void>;
```

Defined in: [prerender.ts:53](https://github.com/simshanith/lit-ui-router/blob/3ab90929a8d23dda96e259d7396a274c5b05398e/packages/ui-router-server/src/prerender.ts#L53)

Where [prerender](../functions/prerender.md) writes: over `node:fs`, a virtual fs, or memory.
`file` arrives with `outDir` already joined on, so a hook writes it
verbatim, creating its directory as needed.

## Parameters

| Parameter | Type |
| ------ | ------ |
| `file` | `string` |
| `body` | `string` |

## Returns

`void` | `Promise`<`void`>