Hi,

If you want to get the data from the backend, you need to do an ajax call and return the data from the controller and create the chart in the .then function of the ajax result.

JavaScript

var ctx = document.querySelector("#_id_of_radar_chart");
ajax.jsonRpc('/controller_name', 'call',{'values to pass to the controller in dictionary format'})
.then(function (result) {
     const myChart = new Chart(ctx, {
        type: 'radar',
        data: {
        labels: result['labels'],
        datasets: [{
        label: 'My First Dataset',
        data: result['datas'],
        fill: true,
        backgroundColor: 'rgba(255, 99, 132, 0.2)',
        borderColor: 'rgb(255, 99, 132)',
        pointBackgroundColor: 'rgb(255, 99, 132)',
        pointBorderColor: '#fff',
        pointHoverBackgroundColor: '#fff',
        pointHoverBorderColor: 'rgb(255, 99, 132)'
        }, {
        label: 'My Second Dataset',
        data: [28, 48, 40, 19, 96, 27, 100],
        fill: true,
        backgroundColor: 'rgba(54, 162, 235, 0.2)',
        borderColor: 'rgb(54, 162, 235)',
        pointBackgroundColor: 'rgb(54, 162, 235)',
        pointBorderColor: '#fff',
        pointHoverBackgroundColor: '#fff',
        pointHoverBorderColor: 'rgb(54, 162, 235)'
        }]
        },
        options: {
        scales: {
        y: {
        beginAtZero: true
        }
        }
        }
    });
 
}

Python

@route(['/controller_name'], type='json')
def controller_name(self, **kwargs):
    #kwargs will have the values passed from the ajax call.
    return {'labels': [label 1, label 2], 'datas': [data 1, data 2]}

Regards