用 reduce 方法

[
{
"name": "432",
"fc_type": 0,
"key": "0"
},
{
"sub_type": 0,
"fc_type": 0,
"key": "0"
},
{
"code": "432",
"fc_type": 0,
"key": "0"
},
{
"model": "432",
"fc_type": 0,
"key": "0"
},
{
"throughput": 423,
"fc_type": 0,
"key": "0"
},
{
"name": "432",
"fc_type": 0,
"key": "1"
},
{
"sub_type": 0,
"fc_type": 0,
"key": "1"
},
{
"code": "432",
"fc_type": 0,
"key": "1"
},
{
"model": "432",
"fc_type": 0,
"key": "1"
},
{
"throughput": 432,
"fc_type": 0,
"key": "1"
}
].reduce((prev, current) => {
  const obj = prev.find(item => item.key === current.key)
  if (obj) {
    //  结果数组中已经有这个 key 了就只添加属性
    Object.assign(obj, current)
  } else {
    prev.push(current)
  }
  return prev
}, [])