浅谈：ES6语法中的解构赋值

<script>

function sum(x, y, z) {

    let total = 0;

    if (x) total += x;

    if (y) total += y;

    if (z) total += z;

    console.log(`total:${total}`); // 注意(``)中的`是tab键上方的按键按下产生的，不是单引号

}

sum(5, "", 9); // total:14

function sum2(...m) {

    let total = 0;

    for (var i of m) {

        total += i;

      }

    console.log(`total:${total}`)

}

sum2(4, 8, 9, 10); // total:31

let sum3 = (...m) => {

    let total = 0;

    for (var i of m) {

        total += i;

      }

    console.log(`total:${total}`);

}

sum3(4, 8, 9, 10); // total:31

var [x,y] = [4,8]  // 数组的解构赋值

console.log(...[4, 8]); // ...arr称为数组的扩展，会打印出 4 8

let arr1 = [1, 3];

let arr2 = [4, 8];

console.log("concat: " + arr1.concat(arr2)); // concat: 1,3,4,8

console.log([...arr1, ...arr2]); //  [1, 3, 4, 8]

var [x,y] = [4,8];

var [x, ...y] = [4, 8, 10, 30]; // 加3个点后，此时y是一种动态类型，此时x对应4，y对应8,10,30。...Arr称为数组的扩展

let [a, b, c] = 'es6'; // a:"e" b:"s"c:"6",分别一一对应，称为字符串的解构

let xy = [...'es6']; // ["e", "s", "6"] 称为字符串的扩展

</script>