[Chartjs]-Update Chart.js data with ajax

It doesn’t work because you initially create the chart with wrong configuration. The labels and datasets arrays must be contained in a data object.

Try this instead:

var chart = new Chart(canvas, {
  type: 'line',
  data: { 
    labels: [],
    datasets: [{
      label: 'My Dataset',
      data: [] 
    }]
  }
});