js 根据数组对象里的某个属性实现顺序或逆序排序

代码如下：

　　　　　function sortBy(attr,rev){

            //第二个参数为true or false 若没有传递 默认升序排列

            if(rev ==  undefined){

                rev = 1;

            }else{

                rev = (rev) ? 1 : -1;

            }

            

            return function(a,b){

                a = a[attr];

                b = b[attr];

                if(a < b){

                    return rev * -1;

                }

                if(a > b){

                    return rev * 1;

                }

                return 0;

            }

        }

        var list = [

            {

                a:8,

                b:[3,4]

            },

            {

                a:1,

                b:[1,2]

            },

            {

                a:18,

                b:[5,6]

            }

        ]

        list.sort(sortBy('a')) // == list.sort(sortBy('a'),true)

        console.log(list);

 

效果如下：

 

 

 逆序：

list.sort(sortBy('a'),false)