ES6数组与字符串解构赋值详解及示例

var arr = [1,2,3];
var a = arr[0];
var b = arr[1];
var c = arr[2];
console.log(a,b,c); // 1 2 3

var arr = [1,2,3];
var [a,b,c] = arr;
console.log(a,b,c); // 1 2 3

let arr = [22, [5,8], 11];
let [a,[b,c],d] = arr;
console.log(a,b,c,d); // 22 5 8 11

let x = 11;
let y = 22;
[y,x] = [x,y];
console.log(x,y); // 22 11

let arr = [22, [5,8], 11];
let [a,[b],c] = arr;
console.log(a, b, c); // 22 5 11
let [m,[,n],o] = arr;
console.log(m, n, o); // 22 8 11

let [m] = "";
console.log(m); // undefined;
let [x,y] = NaN; // NaN is not iterable. 不能被数组解析的值：NaN, undefined, null, {}

let [x,y] = new Set([22, 33]);
console.log(x,y); // 22 33

class Group{
 constructor() {
 }
 next() {
  return {value:'Joh', done: false};
 }
 [Symbol.iterator]() {
  return this;
 }
}
let group = new Group();
let [x,y,z,m,n] = group;
console.log(x,y,z,m,n); // Joh Joh Joh Joh Joh 备注：这里如果类中的next的done为true，那么全为undefined

var [x,w, ...y] = [1,2,3,4,5,6];
console.log(x,w, y); // 1 2 [3,4,5,6]

let [x=15, y] = [undefined, 12];
console.log(x,y); // 15 12
let [m=12, n] = [null, 10];
console.log(m, n); // null 10

var [a,b,c] = 'hello';
console.log(a,b,c); // h e l