el-tbale实现翻页多选保留其他页的选项

　　multipleSelections: [],//当前页选择项
　　selectItem: [],//返回数据对比当前页数据的结果
　　multipleList: []//实际选择项

　　// 确认按钮，返回最后的结果
    getMulRows() {
      const list = []
      this.multipleList.forEach(item => {
        if (item.rows) {
          list.push(...item.rows)
        }
      })
      this.closeClick(list)
    },
    closeClick(row) {
      this.$emit('closeHandler', row)
    },
　　// selection-change当选择项发生变化时会触发该事件
    handleSelectionChange(row) {
      this.multipleSelections = row
    },
　　// select当用户手动勾选数据行的 Checkbox 时触发的事件
　　//select-all当用户手动勾选全选 Checkbox 时触发的事件
　　handleRowSelect(row) {
      let index, object
      this.multipleList.forEach((item, i) => {
        if (item.page === this.dialogPageInfo.page) {
          index = i
          object = item
          return
        }
      })
      if (object) {
        object.rows = [...row]
        this.multipleList[index].rows = [...new Set(object.rows)]
      } else {
        const params = { 'page': this.dialogPageInfo.page, 'rows': [...row] }
        this.multipleList.push(params)
        this.multipleList = [...new Set(this.multipleList)]
      }
    },
　　// 翻页更新数据时调用
    setCheckedRows() {
      this.selectItem = []
      if (this.tableData.length === 0 || this.multipleList.length === 0) return
      const index = this.multipleList.find(item => {
        return item.page === this.dialogPageInfo.page
      })
      if (!index) return
      this.tableData.forEach(item => {
        index.rows.forEach(mItem => {
          if (item.pkId === mItem.pkId) {
            this.selectItem.push(item)
          }
        })
      })
      if (this.selectItem.length > 0) {
        this.$nextTick(() => {
          this.selectItem.forEach(item => {
            this.$refs.table.toggleRowSelection(item)
          })
        })
      }
    }