1.     let arr = [1,6,3,86,33,21]
    2.     let arr2 = [
    3.       {
    4.       name:'dan',
    5.       age:18
    6.       },
    7.       {
    8.       name:'dan2',
    9.       age:32
    10.       },
    11.       {
    12.       name:'dan3',
    13.       age:22
    14.       }
    15.     ]
    16.     function fn(a,b){
    17.       // return a-b;// 从小到大
    18.        return b-a;// 从大到小
    19.     }
    20.     function fn2(a,b){
    21.       return a.age-b.age
    22.     }
    23.     console.log(arr.sort(fn));
    24.     console.log(arr2.sort(fn2))