code: function getLocaleOptions() {
    if (!localeOptions) {
      localeOptions = Object.keys(locales).map(locale => {
        const option = document.createElement('option');
        option.value = locale;
        option.disabled = !localeSupported(locale);
        option.textContent = locales[locale];
        return option;
      });
      Object.freeze(localeOptions);
    }
    return localeOptions;
  }
docs: Create options for all locales and cache the result.