let a= [];
let b= {};
res.data.forEach((item, index) => {
  b.id = index;
  b.name = item.name;
  a.push(b) ;
 })
console.log(a);
为何得到的a 里的数组 是n条 b的最后一条对象

res.data里的数据
0:
id: 0
name: "name1"
1:
id: 1
name: "name2"
2:
id: 2
name: "name3"

a的结果是
0:
id: 2
name: "name3"
1:
id: 2
name: "name3"
2:
id: 2
name: "name3"
要怎么改啊