export function formatAreaTree(list) {
  return list.map(item => {
    const result = {
      label: item.stationName1,
      children: []
    };
    if (item.cityList) {
      result.children = item.cityList.map(city => {
        const cityNode = {
          label: city.stationName2,
          children: []
        };
        if (city.countryList) {
          cityNode.children = city.countryList.map(country => {
            const countryNode = {
              label: country.stationName3,
              children: []
            };
            if (country.stationList) {
              countryNode.children = country.stationList.map(station => {
                const stationNode = {
                  label: station.stationName4,
                  stationId: station.stationId,
                  children: []
                };
                if (station.baojiList) {
                  stationNode.children = station.baojiList.map(baoji => {
                    return {
                      label: baoji.baojiName,
                      id: `${baoji.id}-${station.stationId}`,
                    };
                  });
                }
                return stationNode;
              });
            }
            return countryNode;
          });
        }
        return cityNode;
      });
    }
    return result;
  });
}