JS将对象转为指定格式二维数组对象

api 接口获取的对象数据

{
    "A":[{"car_brand_name":"Alpina","sort":"A"},
         {"car_brand_name":"一汽奥迪","sort":"A"},
         {"car_brand_name":"进口奥迪","sort":"A"},
         {"car_brand_name":"阿尔法-罗密欧","sort":"A"},
         {"car_brand_name":"阿斯顿·马丁","sort":"A"}],
   "B":[{"car_brand_name":"一汽奔腾","sort":"B"},
        {"car_brand_name":"东风本田","sort":"B"},
        {"car_brand_name":"东风标致","sort":"B"},
        {"car_brand_name":"保时捷","sort":"B"},
        {"car_brand_name":"别克","sort":"B"},]
}

需要转成的格式

[
    {
        letter:A,
        data:[
            "Alpina",
            "一汽奥迪",
            "进口奥迪",
            "阿尔法-罗密欧",
            "阿斯顿·马丁"
        ]
    },
    {
        letter:B,
        data:[
            "一汽奔腾",
            "东风本田",
            "东风标致",
            "保时捷",
            "别克"
        ]
    }
]

使用 fon in 转换

//原来的对象 

var  obj  = {}  

var array = []; //定义需要转换的数组  

for (let key in obj) {
    var data = [];  //定义大数组中的小数组
    for(let value in obj[key]) {
        data.push(obj[key][value].car_brand_name)  //先把小数组转换
    }
    array.push({
        letter:key,
        data:data
    })  
}