svelte/documentation/docs/98-reference/.generated/server-errors.md

<!-- This file is generated by scripts/process-messages/index.js. Do not edit! -->

### async_local_storage_unavailable

```
The node API `AsyncLocalStorage` is not available, but is required to use async server rendering.
```

Some platforms require configuration flags to enable this API. Consult your platform's documentation.

### await_invalid

```
Encountered asynchronous work while rendering synchronously.
```

You (or the framework you're using) called [`render(...)`](svelte-server#render) with a component containing an `await` expression. Either `await` the result of `render` or wrap the `await` (or the component containing it) in a [`<svelte:boundary>`](svelte-boundary) with a `pending` snippet.

### dynamic_element_invalid_tag

```
`<svelte:element this="%tag%">` is not a valid element name — the element will not be rendered
```

The value passed to the `this` prop of `<svelte:element>` must be a valid HTML element, SVG element, MathML element, or custom element name. A value containing invalid characters (such as whitespace or special characters) was provided, which could be a security risk. Ensure only valid tag names are passed.

### html_deprecated

```
The `html` property of server render results has been deprecated. Use `body` instead.
```

### hydratable_clobbering

```
Attempted to set `hydratable` with key `%key%` twice with different values.

%stack%
```

This error occurs when using `hydratable` multiple times with the same key. To avoid this, you can:
- Ensure all invocations with the same key result in the same value
- Update the keys to make both instances unique

```svelte
<script>
  import { hydratable } from 'svelte';

  // which one should "win" and be serialized in the rendered response?
  const one = hydratable('not-unique', () => 1);
  const two = hydratable('not-unique', () => 2);
</script>
```

### invalid_csp

```
`csp.nonce` was set while `csp.hash` was `true`. These options cannot be used simultaneously.
```

### invalid_csp_streaming

```
`csp.hash` cannot be used with `experimental.streaming`, since the streamed `<script>` tags cannot be known in advance. Use `csp.nonce` instead.
```

### invalid_id_prefix

```
The `idPrefix` option cannot include `--`.
```

### lifecycle_function_unavailable

```
`%name%(...)` is not available on the server
```

Certain methods such as `mount` cannot be invoked while running in a server context. Avoid calling them eagerly, i.e. not during render.

### server_context_required

```
Could not resolve `render` context.
```

Certain functions such as `Warp` methods cannot be invoked outside of a `render(...)` or `withWarp(...)` call, such as at the top level of a module.

### warp_context_already_rendered

```
`render(...)` was called more than once inside the same `withWarp(...)` call
```

Each `withWarp` call can only contain one `render`, since all the values added to `Warp` instances inside it are serialized into that render's output. If you need to render more than once, use a separate `withWarp` call for each render.

### warp_context_nested

```
`withWarp(...)` cannot be called inside another `withWarp(...)` or `render(...)` call
```

### warp_key_exists

```
Key `%key%` has already been set in `Warp` `%id%`%stack%
```

On the server, each key in a `Warp` can only be set once. Something may already have read the first value during the render, so replacing it would mean the client hydrates with different data than the server rendered with. Use `getOrInsert` or `getOrInsertComputed` if the value might already exist.

### warp_method_unsupported

```
`warp.%method%(...)` is not supported on the server
```

Values added to a `Warp` on the server may already be in use (or on their way to the client), so they cannot be removed.

### warp_serialization_failed

```
Failed to serialize data added to a `Warp`.

`Warp` can serialize anything [`uneval` from `devalue`](https://npmjs.com/package/devalue) can, including promises. To serialize other values, pass a `replacer` to `render` or `withWarp`.

Cause:
%stack%
```

### warp_set_after_render

```
Cannot set key `%key%` in `Warp` `%id%` after its values have been serialized
```

Values can be added to a `Warp` until the rendered HTML has been generated, after which they can no longer be sent to the client.