对象数组去重

 let arr = [
    { id: 1, name: 'Tom' },
    { id: 2, name: 'Jerry' },
    { id: 1, name: 'Tom' },
    { id: 3, name: 'Mickey' },
    { id: 2, name: 'Jerry' }
  ];
// 方法一
const uniqueArr = (arr, key='id') => arr.reduce((prev, cur) => {
    if (!prev.some(item => item[key] === cur[key])) {
      prev.push(cur);
    }
    return prev;
  }, []);
// 方法二
  const duplicateById = (list, uniqueKey='id') => [...list.reduce((prev, cur) => prev.set(cur[uniqueKey], cur), new Map()).values()]
// 输出
console.log(uniqueArr(arr))
console.log(duplicateById(arr))


[
    {
        "id": 1,
        "name": "Tom"
    },
    {
        "id": 2,
        "name": "Jerry"
    },
    {
        "id": 3,
        "name": "Mickey"
    }
]