ES6学习笔记2 解构赋值

{
let a,b,rest
[a,b] = [1,2]
console.log(a,b)
}
{
let a,b,rest
[a,b,...rest] = [1,2,3,4,5,6]
console.log(a,b,rest)

}
{
let a,b
({a,b} = {a:1,b:2})
console.log(a,b)

}
// 默认值，防止左右没有配对成功出现undefind
{
let a,b,c,rest
[a,b,c=3] = [1,2]
console.log(a,b,c)
}

// 实现变量之间交换
{
let a=1;
let b=2;
[a,b] = [b,a]
console.log(a,b)
}
// 快速得到返回值，不需要再通过[0]
{
function f() {
return [1,2]
}
let a,b;
[a,b]=f()
console.log(a,b)
}
// 只取想要的数据
{
function f() {
return [1,2,3,4,5]
}
let a,b,c;
[a,,,b] = f()
console.log(a,b)
}
// 不知道返回数组长度，只想用第一个数值，其它赋值给一个数组
{
function f() {
return [1,2,3,4,5,6]
}
let a,b,c;
[a,...b] = f();
// 混合使用
// [a,,,...b] = f()
console.log(a,b)
}

// 对象结构赋值
{
let o ={p:1,q:true}
let {p,q} = o;
console.log(p,q)
}

// 默认值
{
let {a=3,b=5} = {a:5}
console.log(a,b)
}

// 处理后端返回的json
{
let metaData = {
title:'abc',
test:[{
title:'你好',
desc:'description'
}]
}
let {title:mytitle,test:[{title:ctitle,desc:mydesc}]} = metaData;
console.log(mytitle,ctitle,mydesc)
}