SOURCE

console.log(...[1, 2, 3])
// 1 2 3
console.log(1, ...[2, 3, 4], 5)
// 1 2 3 4 5


function push(array, ...items) {
    array.push(...items);
}
function add(x, y) {
    return x + y;
}
var numbers = [4, 38];
console.log(add(...numbers)); // 42

var array = [1, 2, 3, 4];
console.log(...array);//1 2 3 4 
var str = "String";
console.log(...str);//S t r i n g

//拷贝数组
var array0 = [1,2,3];
var array1 = [...array0];
console.log(array1);//[1, 2, 3]

//拷贝对象
var obj = {
    age:1,
    name:"lis",
    arr:{
        a1:[1,2]
    }
}
var obj2  = {...obj};
console.log(obj2);//{age: 1, name: "lis", arr: {…}}

// rest
// 使用rest参数:
function sumRest (...m) {
    var total = 0; 
    for(var i of m){
        total += i;
    }
    return total;
}
console.log(sumRest(1,2,3));//6

function a(...arg)
{
    console.log(arg);
}
a(1,2,3);
/*
扩展运算符和rest运算符是逆运算
    扩展运算符：数组=>分割序列
    rest运算符：分割序列=>数组


*/