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
  }
}