chartjs plot datetime value with time offset on the grid

Question

I have a ChartJS line chart displaying Datetime values.

Each value is displayed on the chart exactly in the vertical line where the XAxis day label is located.

What I need is to plot the data based on the time for that day. So for example, if I have two data points:

{ t: '2019-08-15T09:00:00Z', y: 0.3 },
{ t: '2019-08-15T17:00:00Z', y: 0.3 }

What I should see is that first data point will be show a little bit offset from the day grid vertical line while the second data point will be ploted to the right of the first point.

Something similar as the next image:

Is this possible?

timclutton timclutton · Accepted Answer · 2019-08-28T08:39:11

That should be the default behaviour for the time axis, assuming it's configured correctly. I've added a couple of data points to your set so as to illustrate in the snippet below.

Also, I see that you've tagged your question as chartjs-2.6.0. Axis handling was significantly improved in more recent releases so upgrade if you can.

new Chart(document.getElementById("chart"), {
  type: "line",
  data: {
    datasets: [{
      data: [{
          t: '2019-08-14T09:00:00Z',
          y: 0.1
        },
        {
          t: '2019-08-15T09:00:00Z',
          y: 0.3
        },
        {
          t: '2019-08-15T17:00:00Z',
          y: 0.3
        },
        {
          t: '2019-08-16T09:00:00Z',
          y: 0.5
        }
      ]
    }]
  },
  options: {
    scales: {
      xAxes: [{
        type: "time",
        time: {
          unit: "day"
        }
      }]
    }
  }
});

<script src="https://cdnjs.cloudflare.com/ajax/libs/Chart.js/2.8.0/Chart.bundle.min.js"></script>
<canvas id="chart"></canvas>

chartjs plot datetime value with time offset on the grid

1 Answers