解构赋值 ...剩余运算符 展开运算符

   let obj={
      query:{
         name:"file",
         pageNo:"6",
         pageSize:"20",
         total:100
      }
   }
   
   //解构赋值 需要哪个用哪个=>total=10设置默认值,无参数时为10=>数据中无初始化为undefined
   let {name,pageNo:pageNo,pageSize:Size,total=10}=obj.query  //pageSize已被更名为Size
   console.log(name,pageNo,pageSize,total)  //下例图片1
    console.log(name,pageNo,pageSize,total) // file 6 20 100

数组解构赋值

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

剩余运算符

     var [a, ...b] = [1,2,3,4,5,6,7,8];
     console.log(a, b); // 1  [2,3,4,5,6,7,8]

展开运算符 //Array from() 与 ... 用途类似

   var [a, ...b] = [1,2,3,4,5,6,7,8];
   console.log(a,b) // 1  [2,3,4,5,6,7,8]
   console.log([...a,b]) //下例图片
   console.log([...b]) //[2, 3, 4, 5, 6, 7, 8]