table 行合併

getSpanArr(data) {
      this.spanArr = [];
      if (data === null) {
        return;
      }
      for (var i = 0; i < data.length; i++) {
        if (i === 0) {
          this.spanArr.push(1);
          this.pos = 0;
        } else {
          if (data[i].index === data[i - 1].index) {  //index爲可合併爲同一行的標誌
            this.spanArr[this.pos] += 1;
            this.spanArr.push(0);
          } else {
            this.spanArr.push(1);
            this.pos = i;
          }
        }
      }
    },