el-table点击全选框只选择部分行

<script>
export default {
    data(){
        return{
            multipleSelection:[],
            selectAllNum:0
        }
    },
    watch: {
      multipleSelection(newValue){
          console.log(newValue);
          if(newValue.length === this.tableData.length){
             this.excludes();
          }
      }  
    },
    methods:{
        handleSelectionAll(val){
            this.$refs.ewTable.clearSelection();
            this.selectAllNum++;
            if((this.selectAllNum)%2===0){
                this.$refs.ewTable.clearSelection();
            }else{
                this.multipleSelection = val;
            }
            console.log(this.multipleSelection);
        },
        excludes(){
            if(this.multipleSelection.length > 0){
                let notOverhulaedList = this.multipleSelection.filter(item=>{
                    return item["检修状态"]==="未检修";
                })
                // console.log(notOverhulaedList);
                this.toggleSelection(notOverhulaedList);
            }else{
                this.toggleSelection();
            }
        },
        toggleSelection(rows) {
            if (rows) {
                rows.forEach(row => {
                    this.$refs.ewTable.toggleRowSelection(row);     
                });
                // 全选选中的未处理的数据
                this.notFishedList = rows;

            } else {
                this.$refs.ewTable.clearSelection();
            }
        },

    }

}
</script>