案例要求：
如有以下两个用户数组，把用户Id相同的过滤掉，然后合并成新的数组
let users1 = [
{
id:1, name:'tom', age: 20},
{
id:2, name:'jack', age: 21},
{
id:3, name:'smith', age: 22}
]
let users2 = [
{
id:3, name:'smith', age: 22},
{
id:4, name:'rose', age: 23},
{
id:5, name:'tina', age: 24},
]
合并后
[
{
id:1, name:'tom', age: 20},
{
id:2, name:'jack', age: 21},
{
id:3, name:'smith', age: 22},
{
id:4, name:'rose', age: 23},
{
id:5, name:'tina', age: 24},
]
实现
先使用…合并成一个新的数组，然后使用reduce方法去除对象中id相同的值
let newArr = [...users1, ...users2]
let obj = {
}
let newUsers = newArr.reduce((item, next) => {
obj[next.id] ? '' : obj[next.id] = true && item.push(next)
return item
}, [])