getLocale (vm) {
    if (!this.selectedLocale) {
      this.selectedLocale = [
        this.options.locale,
        this.i18n(vm),
        'en'
      ].reduce((selection, locale) => {
        if (selection) {
          return selection
        }
        if (locale) {
          const option = parseLocale(locale)
            .find(locale => has(this.options.locales, locale))
          if (option) {
            selection = option
          }
        }
        return selection
      }, false)
    }
    return this.selectedLocale
  }
Select the proper locale to use.