validator/es/lib/isLocale.js

String validation and sanitization

import assertString from './util/assertString';
var 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);
}