Best approach for parent/child relationships and slugs in Sanity.io

defineField({
  name: "slug",
  type: "slug",
  options: { source: "title" },
  group: "content",
}),

	defineField({
		name: 'parent',
		title: 'Kategori',
		type: 'reference',
		to: [{ type: "article" }],
	}),

	defineField({
		name: 'slug',
		title: 'URL',
	  	type: 'slug',
		options: {
			source: (doc, options) => ({ doc, options }),
			slugify: asyncSlugifier
		},
	}),

// Look up the slug of the parent category and append it to the slug of the current document
export async function asyncSlugifier(input: { doc: { title: string; parent: { _ref: string } } }, schemaType: any, context: any) {

	const {getClient} = context
	const client = getClient({apiVersion: '2023-03-01'})

	let pageSlug = input.doc.title
		.toLowerCase()
		.replace(/\s+/g, '-') // slugify the title
		.slice(0, 200);

	// Remove all non-alphanumeric characters (but keep the hyphens)
	pageSlug = pageSlug.replace(/[^A-Za-z0-9-]/g, '');

	if (input.doc.parent) {
		const query = '*[_id == $parentID]';
		const params = {parentID: input.doc.parent._ref}

		var result = await client.fetch(query, params);

		if (result.length > 0) {
			let parentSlug = result[0].slug.current;
			return `${parentSlug}/${pageSlug}`;
		} else {
			return pageSlug;
		}
	} else {
		return pageSlug;
	}	
}