structuredClone not working in Svelte 5

[ciscoheat]

• Before posting an issue, read the FAQ at https://superforms.rocks/faq and search the previous issues.

Description
With Svelte 5, Superforms crashes due to structuredClone not being able to handle Proxy.

A possible fix is to use a different way of cloning, like klona.

[ciscoheat]

Related to get things working with Svelte 5: sveltejs/svelte#9947

[divmgl]

Made a quick fork that uses klona. https://github.com/divmgl/sveltekit-superforms

// package.json
{
  "dependencies": {
    "sveltekit-superforms": "github:divmgl/sveltekit-superforms#ea546c3",
  }
}

[ciscoheat]

That works, but also need the bind:group fix to get things working on Svelte 5. Go to sveltejs/svelte#9947 and give some cheer. :)

[ciscoheat]

It seems like klona doesn't handle Proxy objects well, so it will probably be just-clone in the end. It will also be a v2 feature, since it is quite close to release.

[ciscoheat]

2.0.0-alpha.37 is using just-clone now and it seems to work well in both Svelte 4 and 5.