Element el-table 上移 下移

 //向上移动
  moveUp(index,row) {
      var that = this;
      console.log('上移',index,row);
      console.log(that.imageData[index]);
      if (index > 0) {
          let upDate = that.imageData[index - 1];
          that.imageData.splice(index - 1, 1);
          that.imageData.splice(index,0, upDate);
      } else {
        alert('已经是第一条，不可上移');
      }
  },
//向下移动
moveDown(index,row){
   var that = this;
  console.log('下移',index,row);
  if ((index + 1) === that.imageData.length){
    alert('已经是最后一条，不可下移');
  } else {
    console.log(index);
    let downDate = that.imageData[index + 1];
    that.imageData.splice(index + 1, 1);
    that.imageData.splice(index,0, downDate);
  }
},

@click="moveDown(scope.$index,scope.row)"

@click="moveUp(scope.$index,scope.row)"