JavaScript 代码优化：将区县代码加入城市列表

你可以在这段代码中添加一个功能，将110228放入到北京市下面的城市中。具体的修改如下：\n\njavascript\nfunction useCascaderAreaData() {\n const {\n city_list: city,\n county_list: county,\n province_list: province\n } = areaList;\n const provinceMap = /* @__PURE__ */ new Map();\n Object.keys(province).forEach((code) => {\n provinceMap.set(code.slice(0, 2), makeOption(province[code], code, []));\n });\n const cityMap = /* @__PURE__ */ new Map();\n Object.keys(city).forEach((code) => {\n const option = makeOption(city[code], code, []);\n cityMap.set(code.slice(0, 4), option);\n const province2 = provinceMap.get(code.slice(0, 2));\n if (province2) {\n province2.children.push(option);\n }\n });\n \n // 添加区县到城市中\n const countyCode = '110228';\n const cityCode = countyCode.slice(0, 4);\n const city2 = cityMap.get(cityCode);\n if (city2) {\n city2.children.push(makeOption(county[countyCode], countyCode));\n }\n\n Object.keys(county).forEach((code) => {\n const city2 = cityMap.get(code.slice(0, 4));\n if (city2 && code !== countyCode) {\n city2.children.push(makeOption(county[code], code));\n }\n });\n \n return Array.from(provinceMap.values());\n}\n\n\n这样，110228就会被加入到北京市下面的城市中。