How to Update 2 dataset for 2 lines in a CharJS line graph?

Question

     var ctx = document.getElementById("canvas");
                var Param1Data = {
                    label: "Param1",
                    yAxisID: 'A',
                    data: chartParam1Value,
                    lineTension: 0.5,
                    fill: false,
                    borderColor: 'red'
                };

                var Param2Data = {
                    label: "Param2",
                    yAxisID: 'B',
                    data: chartParam2Value,
                    lineTension: 0.5,
                    fill: false,
                    borderColor: 'blue'
                };

                var MainDataSet = {
                    labels: chartDataValue,
                    datasets: [Param1Data, Param2Data]
                };

                var chartOptions = {
                    legend: {
                        display: true,
                        position: 'top',
                        labels: {
                            boxWidth: 80,
                            fontColor: 'black'
                        }
                    },
                    scales: {
                        yAxes: [{
                            id: 'A',
                            type: 'linear',
                            position: 'left',
                            ticks: {
                                max: 10000,
                                min: 0
                            }
                        }, {
                            id: 'B',
                            type: 'linear',
                            position: 'right',
                            ticks: {
                                max: 10000,
                                min: 0
                            }
                        }]
                    }
                };

                chart = new Chart(ctx, { type: 'line', data: MainDataSet,options: chartOptions});

               // chart = new Chart(ctx, config);  // call for canvas 
            }

When I try to update those 2 data lines using this function, It don't update lines.

    addData()
            {
                     chart.data.labels.push(chartDataValue);
        
                        chart.data.datasets.forEach((dataset) => {
                            dataset.data.push(chartParam1Value);
                        });
        
                        chart.data.datasets.forEach((dataset) => {
                            dataset.data.push(chartParam2Value);
                      });
     chart.update(); //Updating the chart
      }
  setInterval(addData, 3000); // calling update method for new datapoint

I have 2 dataset for 2 lines in CharJS graphs, First data insert draw is perfect in graph but when I try to update the datasets, Its not updating the data through addData() function. can someone show how to update the 2 lines through update function in CharJS graph?

Answer 1

According to the documentation ( https://www.chartjs.org/docs/latest/developers/updates.html#adding-or-removing-data ) after you add your data to the array you will have to call the update method on your chart to update it like this:

             updateChart = (dataset) =>{
                chart.data.datasets.forEach((dataset) => {
                    dataset.data.push(chartParam1Value);
                });

                chart.data.datasets.forEach((dataset) => {
                    dataset.data.push(chartParam2Value);
                });
                chart.update()
             }