get lang () {
    const ret = {}
    XGI18nLang.langKeys.map(key => {
      ret[key] = XGI18nLang.lang[key]
    })
    if (XGI18nLang.lang['zh-cn']) {
      ret.zh = XGI18nLang.lang['zh-cn'] || {}
    }
    return ret
  }
@type {{
  [propName: string]: {
    [propName: string]: string
  }
}}