The properties of AssetStoryblok should be nullable.

[ryami333]

The type of AssetStoryBlok (generated by generate-sb-types) is incorrect. When I leave an asset field empty then the body of that field's JSON looks like this:

{
  "id": null,
  "alt": null,
  "name": "",
  "focus": null,
  "title": null,
  "source": null,
  "filename": "",
  "copyright": null,
  "fieldtype": "asset",
  "meta_data": {}
}

Which does not match the shape of AssetStoryblok:

export interface AssetStoryblok {
  alt?: string;
  copyright?: string;
  id: number;
  filename: string;
  name: string;
  title?: string;
  focus?: string;
}

Related question - why does an empty asset field not just return null/undefined? Why does it return this phantom asset object? That seems like an API bug to me.

If this is intended behaviour, then AssetStoryblok's fields need to be made | null.