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

# Type Alias: FileWriter

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

Defined in: packages/ui-router-server/dist/prerender.d.ts:48

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`>