数据结构：

let address = [
    {
        label: "北京市",
        children: []
    },
    {
        label: "天津市",
        children: []
    },
    {
        label: "上海市",
        children: []
    },
    {
        label: "重庆市",
        children: []
    },
    {
        label: "河北省",
        children: [
            {
                label: "石家庄市"
            },
            {
                label: "唐山市"
            },
            {
                label: "秦皇岛市"
            },
            {
                label: "邯郸市"
            },
            {
                label: "邢台市"
            },
            {
                label: "保定市"
            },
            {
                label: "张家口市"
            },
            {
                label: "承德市"
            },
            {
                label: "沧州市"
            },
            {
                label: "廊坊市"
            },
            {
                label: "衡水市"
            }
        ]
    },
   ]

vscode控制台打印结果：

浏览器运行打印结果：