image.png

去重Set

const arr = ['張三','張三','三張三']
let set = new Set(arr); // set 自帶去重
// Set { '張三', '三張三' }
console.log(set);
console.error(Array.from(set)); // [ '張三', '三張三' ]

可直接在控制臺粘貼打印 f12

let person = [
     {id: 0, name: "小明"},
     {id: 1, name: "小張"},
     {id: 2, name: "小李"},
     {id: 3, name: "小孫"},
     {id: 1, name: "小周"},
     {id: 2, name: "小陳"},   
];

let obj = {};

let peon = person.reduce((cur,next) => {
    obj[next.id] ? "" : obj[next.id] = true && cur.push(next);
    return cur;
},[]) //設置cur默認類型為數組，并且初始值為空的數組
console.log(peon);
// (4) [{…}, {…}, {…}, {…}]0: {id: 0, name: "小明"}1: {id: 1, name: "小張"}2: {id: 2, name: "小李"}3: {id: 3, name: "小孫"}length: 4__proto__: Array(0)

去重reduce

let hash = {};
let config = [{
    name: 2,
    state: true,
    output: 'Y',
}, {
    name: 3,
    state: true,
    output: 'A',
}, {
    name: 5,
    state: true,
    output: 'S',
}, {
    name: 7,
    state: true,
    output: 'B',
}];

config = [...config, {
    name: 3,
    state: false,
    output: 'A',
}]
const newArr = config.reduceRight((item, next) => {
    hash[next.name] ? '' : hash[next.name] = true && item.push(next);
    return item
}, []);
console.log(JSON.stringify(newArr));

// [{"name":3,"state":false,"output":"A"},{"name":7,"state":true,"output":"B"},{"name":5,"state":true,"output":"S"},{"name":2,"state":true,"output":"Y"}]

大神總結：https://www.cnblogs.com/caideyipi/p/7679681.html

原文參考鏈接 https://blog.csdn.net/u010377383/article/details/79645839 （reduce）
https://blog.csdn.net/original_heart/article/details/79491768

擴展文章

js 刪除兩個數組中id相同的對象

image.png