ES6-扩展运算符、set、对象方法扩展

数组合并

 const arr1 = ["11","22","33"];
        const arr2 = ["44","55"];
        const result = arr1.concat(arr2);
        const resultArr = [...arr1,...arr2];
        console.log(result);
        console.log(result);

数组克隆

const arr3 = ["11","22","33"];
        const result1 =[...arr3];
        console.log(result1);

将伪数组转化为真正的数组

  const divs = document.querySelectorAll('div');
        const divArr = [...divs];
        console.log(divArr);

set

set
添加 add
删除 delete
清空 clear

数组去重

 let arr = [1,2,3,4,5,2,3,4];
        let result = [...new Set(arr)];
        // console.log(result);//[ 1, 2, 3, 4, 5 ]

交集

 let arr = [1,2,3,4,5,2,3,4];
    let arr1 = [2,3,4,2,3,7,9];
        let result1 = [...new Set(arr)].filter(item => new Set(arr1).has(item));
        // console.log(result1);//[ 2, 3, 4 ]

并集

 let arr = [1,2,3,4,5,2,3,4];
 let arr1 = [2,3,4,2,3,7,9];
   let union =  [...new Set([...arr,...arr1])];
        // console.log(union);// [ 1, 2, 3, 4, 5, 7, 9 ]

差集

 let arr = [1,2,3,4,5,2,3,4];
 let arr1 = [2,3,4,2,3,7,9];
let diff = [...new Set(arr)].filter(item => !(new Set(arr1).has(item)));
        console.log(diff);

对象方法扩展

 // Object.is


        // Object.assign   对象合并覆盖  两个对象有重名的key，后面的会覆盖前面的

        let student = {
            name:'tom',
            age:18,
            sex:'boy'
        }

        let student2 = {
            name:'gai',
            age:28
        }
        let result = Object.assign(student,student2);
        /* 
        student = {
            name:'gai',
            age:28,
            sex:'boy'
        }
         */

        // Object.setPrototypeOf  Object.getPrototypeOf 设置原型对象 获取原型对象