@ai-sdk/svelte - beforeUpdate(...) cannot be used in runes mode

[phenomen]

Description

After updating to Svelte 5, I get this error:

Uncaught Svelte error: lifecycle_legacy_only
`beforeUpdate(...)` cannot be used in runes mode

In the log it points to this code somewhere in @ai-sdk/svelte

Code example

<script lang="ts">
	import { useCompletion } from "@ai-sdk/svelte";

	const { input, handleSubmit, completion, isLoading } = useCompletion({
		api: "/api/openai/format",
	});

	let output = $derived($completion);
</script>

[tguelcan]

Any workaround?

[chengwan7]

Encountered the same issue after upgrading to svelte 5.

[didier]

Yep this is fully broken in Svelte 5. Seems like a high priority issue to fix.

[phenomen]

Apparently, the code comes from @ConsoleTVs/sswr which is deprecated/unmaintained.