我這里是根據x軸數組的最后一個元素與series里面的color的val來做對比，如果相等就改變顏色

  myChart.setOption({
              xAxis: {
                data: result.dep_data
              },
              series: [
                {
                  data: result.data,
                  itemStyle: {
                      normal: {
                          color:(val) => {
                            console.log("==》",val)
                            var valLength = result.dep_data.length
                            var newVal =  result.dep_data[valLength-1]
                            console.log("==>",newVal)
                              if (val.name == result.dep_data[valLength-1]) {
                                  return '#F7782C'
                              } else{
                                return '#5470c6'
                              }
                          },
                      },
                  },
                }
              ]
            })