js ... 使用

arr1 = [1,3,5,7,9]
arr2 = [2,4,6,8,10]

console.log(...arr1) // 展开数组
let arr3 = [...arr1, ...arr2] // 连接数组


// 传参
function sum(...number){
      return numbers.reduce((preValue, currentValue)=>{
　　　　return preValue + currentValue
　　})   
}
sum(1,2,3,4,5,6)

// 复制对象
let a = {"name": "刘勇", "age": 18}

b = {...a} // 深拷贝
c = a // 浅拷贝

// 复制同时修改
d = {...a, "name": "老刘"}