get fields from relationship as slug

[tariwiencke]

I want to create a slug for a product based on its brand's title

example: slug = id + brand.title + title

Here is my config:

export const Objects: CollectionConfig = {
  slug: 'objects',
  admin: {
    useAsTitle: 'title',
  },
  fields: [
    {
      name: 'title',
      type: 'text',
      required: true,
    },
    {
      name: 'brand',
      type: 'relationship',
      relationTo: 'brands',
      required: true,
  },
]
}

I already tried different approaches:

1. Boolean Virtual Fields doesn't have access to fields other then id of brand

2. Slug Field can only take one field.

3. String Path Virtual Fields can only take a single field

4. collection hooks cant override the collection

hooks: {
    afterRead: [
      async ({ doc }) => {
        const slug = 'slug'
        return { ...doc, slug }
      },
    ],
  },