ECMAScript5/6新特性之解构表达式

<script>
   let arr =[2,3,4];
   let x = arr[1];
   let y = arr[2];
   let m = arr[1],n=arr[2];
   /*解构表达式*/
    //数组中取值
    let [,a,b] = arr;
   console.log(a+":"+b);
   //数组中取数组
   let [,...brr] = arr;
   console.log(brr);
   //取对象的属性
    let p ={name:"jack",age:21,girl:{name:"smallJack",age:1}}
    let {name,age}=p;
    console.log(name+":"+age)
    //取属性赋给新变量
    let {name:userName,age:userAge}=p;
    console.log(userName+":"+userAge)
    //取复杂对象的属性
    let e ={name:"jack",age:21,girl:{name:"smallJack",age:1}}
    let {girl:{name:smallname,age:smallage}} = e;
    console.log(smallname+":"+smallage)
    //拷贝对象的内容
    let {...obj} = e;
    console.log(obj)
</script>