app/services/asserts/NullableAssert.ts

import type { AssertRule } from '~/types/interfaces'
import { useI18n } from 'vue-i18n'

export class NullableAssert implements AssertRule {
  supports(key: string): boolean {
    return key === 'nullable'
  }

  createRule(criteria: boolean): (value: unknown) => true | string {
    const { t } = useI18n()
    return (value: unknown) =>
      !criteria
        ? (value !== null && !!value) || t('please_enter_a_value')
        : true
  }
}