JS合并数组对象中key相同的数据（将数组里某个属性相同的对象合并成一个数组）两种方案

let tempArr = [];
let Data = [];
for (let i = 0; i < resData.length; i++) {
   if (tempArr.indexOf(resData[i].tagName) === -1) {
     Data.push({
       tagName: resData[i].tagName,
       dataInfo: [resData[i]]
     });
     tempArr.push(resData[i].tagName);
   } else {
     for (let j = 0; j < Data.length; j++) {
       if (Data[j].tagName == resData[i].tagName) {
         Data[j].dataInfo.push(resData[i]);
         break;
       }
     }
   }
 }
 console.log(Data);

let dataInfo = {};
resData.forEach((item, index) => {
    let { tagName } = item;
    if (!dataInfo[tagName]) {
        dataInfo[tagName] = {
            tagName,            
            child: []
        }
    }
    dataInfo[tagName].child.push(item);
});
let list = Object.values(dataInfo); // list 转换成功的数据
console.log(list)