Chart updates as data arrives

site.js

connection.on("newData", function (time, speed, count) {

  // This subtract causes the data to be placed
  // in the centre of the chart as it arrives, 
  // which I personally think looks better...
  var dateValue = moment(time).subtract(5, 'seconds');

  speedValue.innerText = speed;
  countValue.innerText = count;

  // append the new data to the existing chart data
  myChart.data.datasets[0].data.push({
    x: dateValue,
    y: speed
  });

  // update chart datasets keeping the current animation
  myChart.update({
    preservation: true
  });
});