扩展运算符能将数组转换为逗号分割的参数序列

const arr = ['1','2','3']

function get(){
    console.log(arguments) // 展开数组
}
get(...arr)

数组合并

const arr1 = ['1','2','3']
const arr2 = ['4','5','6']

const total = [...arr1,...arr2]

数组克隆

const arr1 = ['1','2','3']
const arr2 = [...arr1]

将伪数组转为真正的数组

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

在函数中使用

// 接收不固定的参数
function sum(...numbers){
    return numbers.reduce((preValue,currentValue)=>{
        return preValue + currentValue
    })
}
console.log(sum(1,2,3,4));

构造字面量对象时使用展开语法

let person = {name:'tom',age:18}
let person2 = {...person} // 深拷贝
//console.log(...person); //报错，展开运算符不能展开对象
person.name = 'jerry'

合并并修改

let person = {name:'tom',age:18}
let person3 = {...person,name:'jack',address:'地球'}
console.log(person3)