ES6数组解构赋值

ES6 允许按照一定模式，从数组和对象中提取值，对变量进行赋值，这被称为解构。

let a = 1;
let b = 2;
let c = 3;


let [a, b, c] = [1, 2, 3];  //ES6写法

结构例子：

let [foo, [[bar], baz]] = [1, [[2], 3]];
foo // 1
bar // 2
baz // 3

let [ , , third] = ["foo", "bar", "baz"];
third // "baz"

let [x, , y] = [1, 2, 3];
x // 1
y // 3

let [head, ...tail] = [1, 2, 3, 4];
head // 1
tail // [2, 3, 4]

let [x, y, ...z] = ['a'];
x // "a"
y // undefined
z // []