table自定义序号

columns: [
         {
         type: 'index',
         width: 60,
         align: 'center',
         indexMethod: (row) => {
         return (row._index + 1) + (this.size * this.current) - this.size;
        //this.size是当前table显示的页数, current是当前处在的页数
         }
         },
         {
         title: '姓名',
         key: 'name'
         }
         ],