js 原生对象排序

//对象属性排序
        function compare(propertyName) { 
            return function (object1, object2) { 
                var value1 = object1[propertyName]; 
                var value2 = object2[propertyName]; 
                if (value2 < value1) { 
                return -1; 
                } 
                else if (value2 > value1) { 
                return 1; 
                } 
                else { 
                return 0; 
                } 
            } 
        }
        var data = obj[0]["day"]; 
       data.sort(compare("time")).reverse(); 

var obj = [{
"name":"T",
"day":[
{
"time":"3",
"price":"30"
},
{
"time":"5",
"price":"50"
},
{
"time":"6",
"price":"60"
},
{
"time":"7",
"price":"70"
}
]
}
]