@skhemata/skhemata-form/src/validator/lib/isLocale.js

Skhemata Form Web Component. This web component can be used as base web component when working with forms and inputs.

import assertString from './util/assertString';

const localeReg = /^[A-z]{2,4}([_-]([A-z]{4}|[\d]{3}))?([_-]([A-z]{2}|[\d]{3}))?$/;

export default function isLocale(str) {
  assertString(str);
  if (str === 'en_US_POSIX' || str === 'ca_ES_VALENCIA') {
    return true;
  }
  return localeReg.test(str);
}