Reusable React TypeScript equality validator (for Ant)

ts_validator.ts

import { useMemo } from 'react';
import { TFunction } from 'i18next';
import { useTranslation } from 'react-i18next';
import { RuleObject, RuleRender } from 'antd/lib/form';
import { StoreValue } from 'antd/lib/form/interface';

const equalTo = (
  t: TFunction,
): ((field: string, translation_key?: string) => RuleRender) => {
  /**
   * equalTo creates dynamic and reusable form field equality validator.
   *
   * Used as validator by invoking:
   *    (field="password", "password.notEqual")
   *
   * Returns Validator object:
   *    validator: (rule: RuleObject, value: StoreValue): Promise<any>
   *
   * @param t {TFunction}
   */
  return (field, translation_key) => {
    return ({ getFieldValue }): RuleObject => ({
      validator(rule: RuleObject, value: StoreValue) {
        if (!value || getFieldValue(field) === value) {
          return Promise.resolve();
        }
        return translation_key
          ? Promise.reject(
              t(translation_key, {
                defaultValue: 'Values you entered do not match!',
              }),
            )
          : Promise.reject('Values you entered do not match!');
      },
    });
  };
};

const useFormRules = () => {
  const { t } = useTranslation();

  return useMemo(
    () => ({
      equalTo: equalTo(t),
    }),
    [t],
  );
};

export default useFormRules;