Chartjs-Chart.js remove shadow from line chart

You can do it in two ways:

1. Setting the line configuration in global options.

var options = {
  elements: {
    line: {
      tension: 0
    }
  }
};

2. Setting lineTension to 0 in datasets.

var chartData = {
  labels: labels,
  datasets: [{
    label: "Chart Data",
    lineTension: 0,           
    data: someData,
  }]
};