Javascript 在angular 8中使用chart.js仅激活一次单击点折线图

折线图当我单击任何特定点时，我获得了数据，但问题是我想显示该特定点处于活动状态，当我单击任何其他点时，第一个点想显示为非活动状态，第二个点显示为活动状态

折线图：

这是我的折线图代码

chartClicked(e) {
    var activePoints = this.Linechart.getElementsAtEventForMode(
      e,
      "point",
      this.Linechart.options
    );
    var firstPoint = activePoints[0];

    var label = this.Linechart.data.labels[firstPoint._index];
    var value = this.Linechart.data.datasets[firstPoint._datasetIndex].data[
      firstPoint._index
    ];


    let existingPoints = this.Linechart.data.labels;

    var elementIndex = activePoints[0]._index;

    this.abcd = [];

    existingPoints.forEach(element => {
      console.log(this.abcd);
      if (element === label) {
        this.addPointConlor = this.Linechart.data.datasets[0].pointBackgroundColor[
          elementIndex
        ] = "red";
      } else {
        this.addPointConlor = this.Linechart.data.datasets[0].pointBackgroundColor[
          elementIndex
        ] = "blue";
      }
    });

这是我的折线图代码

lineCart() {
    const abc = [];
    this.Linechart = new Chart("canvasGraph", {
      type: "line",
      // label : "sagar ",

      data: {
        // labels: this.Xdata,
        labels: ["1-10-2019","2-10-2019","3-10-2019","4-10-2019","5-10-2019","6-10-2019","7-10-2019"],
        datasets: [
          {
            data: [100,150,500,200,111,530,160],
            // data: this.Ydata,
            borderColor: "#ed1c24",
            backgroundColor: "transparent",
            radius: 5,
            label: "Request Chart",
            pointBackgroundColor: this.abcd
            //  fill : 'red',
            // pointHoverBackgroundColor : 'red',
          }
        ]
      },

      options: {
        onClick: this.chartClicked.bind(this),
        elements: {
          line: {
            tension: 0
          }
        },

        legend: {
          display: true
        },
        scales: {
          xAxes: [
            {
              display: true
            }
          ],
          yAxes: [
            // {
            //   display: true
            // }
            {
              stacked: true
            }
          ]
        }
      }
    });

    // });
  }