解构赋值

// 分类 数组解构赋值 对象解构赋值 字符串解构赋值 布尔值解构赋值 函数参数解构赋值 数值解构赋值
{
  let a,b,rest;
  [a,b]=[1,2]
  console.log(a,b)
}
// 1 2
{
  let a,b,rest;
  [a,b,...rest] = [1,2,3,4,5,6]
  console.log(a,b,rest)
}
// 1 2 [3,4,5,6]
{
  let a,b;
  ({a,b} = {a: 1,b:2})
  console.log(a,b)
}
//1 2
{
  let a,b,c,rest;
  [a,b, c=3]=[1,2]
  console.log(a,b,c)
}
//1 2 3
{
  let a,b,c,rest;
  [a,b, c]=[1,2]
  console.log(a,b,c)
}
//1 2 undefined

{
  let a = 1 ;
  let b = 2 ;
  [a,b] = [b,a]
  console.log(a,b)
}
// 2 1
{
  function f() {
    return [1,2]
  }
  let a,b;
  [a,b] = f();
  console.log(a,b)
}
// 1 2

{
  function f() {
    return [1,2,3,4]
  }
  let a,b,c;
  [a,,,c] = f()
  console.log(a,c)
}
// 1 4

{
  function f() {
    return [1,2,3,4]
  }
  let a,b,c;
  [a,...c] = f()
  console.log(a,c)
}
// 1 [2,3,4]

{
  function f() {
    return [1,2,3,4]
  }
  let a,b,c;
  [a,,...c] = f()
  console.log(a,c)
}
// 1 [3,4]

{
  let o = {p:42,q: true}
  let {p,q} = o
  console.log(p,q)
}
//42 true

{
  let {a=10,b=5} = {a:3}
  console.log(a,b)
}
// 3,5

{
  let metaData = {
    title: 'abc',
    test: [{
      title: 'test',
      desc: 'descript'
    }]
  }
  let {title: esTitle,test: [{title: cnTitle}]} = metaData
  console.log(esTitle, cnTitle)
}
// abc test