Issue with slug auto-generation in Sanity.io schema

import {defineType, defineField} from 'sanity'

export default defineType({
  type: 'object',
  title: 'Swatch',
  name: 'swatch',
  fields: [
    defineField({
      title: 'Name',
      name: 'name',
      type: 'string',
      validation: (Rule) => Rule.required(),
    }),
    defineField({
      title: 'Handleized name',
      name: 'handle',
      type: 'slug',
      options: {
        source: 'name',
        disableArrayWarning: true,
      },
      description: "",
      validation: (Rule) => Rule.required(),
    }),
    defineField({
      title: 'Color',
      name: 'color',
      type: 'color',
      validation: (Rule) => Rule.required(),
    }),
  ],
  preview: {
    select: {
      title: 'name',
      subtitle: 'color.hex',
      media: 'color',
    },
    prepare({title, subtitle, media}) {
      return {
        title,
        subtitle,
        media: <div style={{backgroundColor: media.hex, width: '100%', height: '100%'}} />,
      }
    },
  },
})

source: (_, context) => context.parent.name,