I am updating my chartjs element with this code:

 updateDeumdata: function (obj) {
            deumChart.data.labels.push(obj.x);
            deumChart.data.datasets[0].data.push(obj.y)
            deumChart.update();
        }

The issue is that this code adds a new label as first element, and a data (y) as last element without a label. What's wrong? AFAIK .push should add at the end of the array.