Sync slug field only if empty

I’m using the sync and wizard option on the slug field in a blueprint to recreate something like Kirby’s Title and Url Appendix fields (shown when creating a new page or editing a page in the panel). In Kirby, the Url Appendix Field only syncs with Title if it is empty. When there already is a value in Url Appendix the field doesn’t sync. Is this possible with the slug field?

Was able to solve this by extending k-slug-input:

// New `SlugInput.vue`

export default {
  extends: 'k-slug-input',

  data() {
    return { wasEmptyOnCreate: false }

  created() {
    this.wasEmptyOnCreate = !this.value

  computed: {
    // Conditionally disable the `sync` prop
    sync() {
      return this.wasEmptyOnCreate ? this.$options.propsData.sync : null