//option                    
tooltip: {

                        trigger: 'axis',

                        axisPointer: {

                            label: {

                                show: true,

                                fontSize: 15

                            }

                        },

                        formatter: this.formatter

                    }, 

// formatter  function

formatter (params){

        let temp=[];

        let temp2='';

        let leftSide='';

        let rightSide='';

        for( let item of params){

            temp.push({

                seriesName:item.seriesName,

                value:item.value

            })

        }

        let arr=temp.sort(this.sortValue);

        let midValue=Math.ceil(arr.length/2);

        for(let [key,item] of arr.entries()){

            item.seriesName="测试数据";

            if(key< midValue&&midValue>4){

                if(isNaN(item.value)){

                    leftSide+=`${item.seriesName}: 无数据<br>`;

                }else{

                    leftSide+=`${item.seriesName}: ${item.value}<br>`;

                }

            }else{

                if(isNaN(item.value)){

                    rightSide+=`${item.seriesName}: 无数据<br>`;

                }else{

                    rightSide+=`${item.seriesName}: ${item.value}<br>`;

                }

            }

        }

        temp2=`<div class="my-flex">

            <div>${leftSide}</div>

            <div style="margin-left:20px;">${rightSide}</div>

            </div>`;

        return temp2;

    },