new Set去重的用法

使用Set数据结构去除重复对象：new Set(strings)进行转型。因为Set数据结构并非真正的数组，它类似于数组，并且成员值都是唯一的，没有重复，所以可以用来做去重操作。但是因为它是一个类似数组结构，所以需要转型为真正的数组去使用。所以需要用Array.from

new Set()里面需要接的是strings类型
 const list1 =[" { name: '张三', age: 18, address: '北京' }"," { name: '张三', age: 18, address: '北京' }"]
 console.log('去重',new Set(list1))//{" { name: '张三', age: 18, address: '北京' }"}

打印结果:

image.png

2.如果里面不是一个string类型，而是对象不会去重:

const list1 =[{ name: '张三', age: 18, address: '北京' },{ name: '张三', age: 18, address: '北京' }]
console.log('去重',new Set(list1))

打印结果如下:

image.png

案例:

const list =[
    { name: "张三", age: 18, address: "北京" },
    { name: "李四", age: 20, address: "天津" },
    { name: "张三", age: 18, address: "北京" },
]

其中张三和李四为重复对象；
使用Set数据结构去除重复对象
解析:因为数组里面是对象，所以我们这边先用map用JSON.stringify进行转化成string类型

const strings = list.map((item) => JSON.stringify(item))
    console.log('strings', strings) //['{"name":"张三","age":18,"address":"北京"}', '{"name":"李四","age":20,"address":"天津"}', '{"name":"张三","age":18,"address":"北京"}']

然后就可以用new Set对这个数组进行去重，然后再用Array.from转化为真正的数组，

const removeDupList = Array.from(new Set(strings))
console.log('removeDupList',removeDupList)//['{"name":"张三","age":18,"address":"北京"}', '{"name":"李四","age":20,"address":"天津"}']

打印出来这就已经去重了:

image.png

然后再把数组里面的字符串类型转化为对象类型:

const removeDupList = Array.from(new Set(strings))
const result = removeDupList.map((item) => JSON.parse(item))
console.log('result',typeof result)

image.png