以下代码放到nodejs中运行

a.js文件内容，vant的数据，来自import { areaList } from '@vant/area-data'，形如：

const fs = require('fs');

const a = require('./a.js');

const b = transformData(a);
fs.writeFileSync('./b.js', JSON.stringify(b,null,2));

function transformData(data) {
  const result = [];

  // 处理省级数据
  for (const [provinceCode, provinceName] of Object.entries(data.province_list)) {
    const provinceObj = {
      children: [],
      label: provinceName,
      value: provinceCode
    };

    // 处理市级数据
    for (const [cityCode, cityName] of Object.entries(data.city_list)) {
      const provinceCode_ = provinceCode.slice(0, 2);
      if (cityCode.startsWith(provinceCode_)) {
        const cityObj = {
          children: [],
          label: cityName,
          value: cityCode
        };

        // 处理区级数据
        for (const [countyCode, countyName] of Object.entries(data.county_list)) {
          const cityCode_ = cityCode.slice(0, 4);
          if (countyCode.startsWith(cityCode_)) {
            const countyObj = {
              label: countyName,
              value: countyCode
            };

            cityObj.children.push(countyObj);
          }
        }

        provinceObj.children.push(cityObj);
      }
    }

    result.push(provinceObj);
  }

  return result;
}

导出数据：