方法：js 数组对象根据多个字段进行分类

这里举个例子是根据两个字段分组，多个的话稍微加个判断就能用

例：根据id和groupname进行分类，代码如下

var arr = [
          { "id": "1", "groupname": "值1", "value": "11" },
          { "id": "1", "groupname": "值1", "value": "12" },
          { "id": "1", "groupname": "值1", "value": "13" },
 
          { "id": "2", "groupname": "值1", "value": "22" },
          { "id": "2", "groupname": "值1", "value": "23" },
          { "id": "2", "groupname": "值1", "value": "24" },
          { "id": "2", "groupname": "值1", "value": "25" },
 
          { "id": "3", "groupname": "值2", "value": "33" },
 
          { "id": "4", "groupname": "值2", "value": "44" },
          { "id": "4", "groupname": "值2", "value": "45" },
 
          { "id": "5", "groupname": "值3", "value": "55" },
 
          { "id": "6", "groupname": "值3", "value": "66" }
        ];
 
        var map = [
          {
            id: arr[0].id,
            groupname: arr[0].groupname,
            item: [arr[0]],
          }
        ]
        for (var i = 1; i < arr.length; i++) {
          let bool = map.some((it)=>{
            if((arr[i].id == it.id) && (arr[i].groupname == it.groupname)){
              it['item'].push(arr[i])
            }
            return ((arr[i].id == it.id) && (arr[i].groupname == it.groupname))
          })
          if(!bool){
            map.push({
                id: arr[i].id,
                groupname: arr[i].groupname,
                item: [arr[i]],
              })
          }
        }
        console.log(map);

结果如下