vue数组对象根据某个属性值排序

methods: {
 getsort() {
   const arr = [{name: '苹果',num: 10},{name: '柚子',num: 6}]
   arr.sort(this.sortBy("num")) //  [{name: '柚子',num: 6},{name: '苹果',num: 10}]
 }
sortBy(i) {
     return function(a,b) {
       return a[i] - b[i] //  a[i] - b[i]为正序，倒叙为  b[i] - a[i] 
     }
   },
}