JavaScript ES6解构运算符的理解和运用

let [a,b,c] = [1,2,3];
// let a = 1, b = 2, c = 3;

// 数组
 let [a, [[b], c]] = [1, [[2], 3]];
	console.log(a); // 1
	console.log(b); // 2
	console.log(c); // 3
// 对象
 let obj = { x: ['hello', {y: 'world'}] };
 let { x: [x,{ y }] } = obj;
	console.log(x); // hello
	console.log(y); // world

// 数组
 let [a, , b] = [1, 2, 3];
	console.log(a); // 1
	console.log(b); // 3

// 对象
 let obj = { x: ['hello', { y: 'world' }] };
 let { x: [x, { }] } = obj;
	console.log(x); // hello

// 数组
 let [a = 1, b] = [];
	console.log(a); // 1
	console.log(b); // undefined

// 对象
 let obj = { x: [{ y: 'world' }] };
 let { x: [{ y }, x] } = obj;
	console.log(x); // undefined
	console.log(y); // world

// 数组
 let [a, ...b] = [1, 2, 3];
	console.log(a); // 1
	console.log(b); // [2,3]

// 对象
 let {a, b, ...rest} = {a: 10, b: 20, c: 30, d: 40};
	console.log(a); // 10
	console.log(b); // 20
	console.log(rest); // { c: 30, d: 40 }

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

// 当解构模式有匹配结果，且匹配结果是 undefined 时，会触发默认值作为返回结果。
 let [a = 2] = [undefined]; 
	console.log(a); // 2
// 对象
let {a = 10, b = 5} = {a: 3};
 	console.log(a); // 3
 	console.log(b); // 5

let a = 1;
let b = 2;
[a,b] = [b,a];
	console.log(a); // 2
	console.log(b); // 1

// 1. 浅克隆与合并
let name = { name: "aaa" }
let age = { age: 'bbb' }
let person = { ...name, ...age }
console.log(person) // { name: "aaa", age: 'bbb' }

let a = [1,2,3];
let b = [4,5];
let c = [...a,...b];
console.log(c); // [1,2,3,4,5]

// 2. 提取JSON数据
let JsonData = { id: 10, status: "OK", data: [111, 222] } 
let { id, status, data: numbers } = JsonData; 
console.log(id, status, numbers); //10 "OK" [111, 222]

// 3. 函数参数的定义
// 参数有序
function fun1([a, b, c]) { console.log(a, b, c) } 
fun1([1, 2, 3]); // 1 2 3

// 参数无序
function fun2({ x, y, z }) { console.log(x, y, z) } 
fun2({ z: 3, x: 2, y: 1 }); // 2 1 3

// 参数有默认值
function fun3 ([a=1,b]) {
console.log(a,b);
}
fun3([,3]) // 1 3

var merge = function(nums1, m, nums2, n) {
    nums1.length=m;
    nums2.length=n;
    nums1.push(...nums2);
    let arr=nums1.sort((a,b)=>{
        return a-b;
    })
    return arr;
};