Pie chart.js - display a no data held message

7
votes

I'm using chart.js Version: 2.8.0 to display a bar chart and a pie chart.

The non-empty bar and pie charts display as I want.

However, when the bar and pie charts are empty or have zero data to display, is there a standardised option to display a "No data to display!" message for both the bar and pie charts that can be shown in place of the empty or zero data.

I've searched google for a plugin and SO for a solution, but the options I've found either don't work at all or don't work for the latest version of chartjs.

Here is my empty pie chart:

new Chart(document.getElementById('pieChartExample01'), {
    type: 'pie',
    data: {
        labels: [
            'Views',
            'Print Requests',
            'PDF Downloads',
            'DOCX Downloads',
        ],
        datasets: [{
            backgroundColor: [
                'rgba(71, 101, 160, 0.3)',  // #4765a0.
                'rgba(0, 0, 0, 0.3)',  // #000000.
                'rgba(52, 137, 219, 0.3)',  // #3489db.
                'rgba(179, 179, 179, 0.3)',  // #b3b3b3.
            ],
            hoverBackgroundColor: [
                'rgba(71, 101, 160, 0.6)',  // #4765a0.
                'rgba(0, 0, 0, 0.6)',  // #000000.
                'rgba(52, 137, 219, 0.6)',  // #3489db.
                'rgba(179, 179, 179, 0.6)',  // #b3b3b3.
            ],
            borderWidth: 1,
            hoverBorderWidth: 2,
            borderColor: [
                'rgba(71, 101, 160, 1)',  // #4765a0.
                'rgba(0, 0, 0, 1)',  // #000000.
                'rgba(52, 137, 219, 1)',  // #3489db.
                'rgba(179, 179, 179, 1)',  // #b3b3b3.
            ],
            borderAlign: 'inner',
            data: [0, 0, 0, 0]
      }]
    },
    options: {
        title: {
          display: false,
          text: 'Overall Activity'
        }
    }
});
<canvas id="pieChartExample01" width="25" height="25"></canvas>
<script src="https://cdn.jsdelivr.net/npm/[email protected]"></script>

This is what I would like the empty pie chart to display as (preferably with the labels):

enter image description here

UPDATE TO ANSWER - 13th April, 2019

Using the answer provided by Core972, I decided to extrapolate the accepted answer so that the message of choice can be displayed over a bar chart and a pie chart with the data labels displayed rather than just a blank canvas.

Here's the solution that I came up with that works with pie and bar charts.

I haven't tested the other types of charts, but I'm presuming they would work with the same approach.

A few pointers to note:

  1. When there is zero data to display, the borders must also be zero, otherwise an annoying border displayed as a single line is displayed. Use a simple if else condition to hide show the borders if necessary.

  2. Use an if else condition to display / hide the message. If there is data, hide the message, else display the message if data is zero.

  3. I've only tested this approach with Chrome & Firefox and seems to work OK.

I hope that this can help someone! Enjoy!

PIE CHART WITH DATA LABELS DISPLAYED AND A FLOATING MESSAGE:

new Chart(document.getElementById('pieChartExample01'), {
    type: 'pie',
    data: {
        labels: [
            'Views',
            'Print Requests',
            'PDF Downloads',
            'DOCX Downloads',
        ],
        datasets: [{
            backgroundColor: [
                'rgba(71, 101, 160, 0.3)',  // #4765a0.
                'rgba(0, 0, 0, 0.3)',  // #000000.
                'rgba(52, 137, 219, 0.3)',  // #3489db.
                'rgba(179, 179, 179, 0.3)',  // #b3b3b3.
            ],
            hoverBackgroundColor: [
                'rgba(71, 101, 160, 0.6)',  // #4765a0.
                'rgba(0, 0, 0, 0.6)',  // #000000.
                'rgba(52, 137, 219, 0.6)',  // #3489db.
                'rgba(179, 179, 179, 0.6)',  // #b3b3b3.
            ],
            borderWidth: 0,
            hoverBorderWidth: 0,
            borderColor: [
                'rgba(71, 101, 160, 1)',  // #4765a0.
                'rgba(0, 0, 0, 1)',  // #000000.
                'rgba(52, 137, 219, 1)',  // #3489db.
                'rgba(179, 179, 179, 1)',  // #b3b3b3.
            ],
            borderAlign: 'inner',
            data: [0, 0, 0, 0]
      }]
    },
    options: {
        title: {
          display: false,
          text: 'Overall Activity'
        }
    }
});
<div style="width: 100%; height: 100%; position: relative;">
    <div style="text-align: center; width: 100%; height: 100%; position: absolute; left: 0; top: 100px; z-index: 20;">
        <b>No data for you today!</b>
    </div>
    <canvas id="pieChartExample01" width="25" height="25"></canvas>
    <script src="https://cdn.jsdelivr.net/npm/[email protected]"></script>
</div>
3
javascripthtmlchartschart.js

3 Answers

4
votes

Here an example working with chart.js 2.8.0

<canvas id="pieChartExample01" width="25" height="25"></canvas>
<div id="no-data">Nothing to display</div>

...
options: {
  title: {
    display: false,
    text: 'Overall Activity'
  },
  animation: {
    onComplete: function(animation) {
      var firstSet = animation.chart.config.data.datasets[0].data,
        dataSum = firstSet.reduce((accumulator, currentValue) => accumulator + currentValue);

      if (typeof firstSet !== "object" || dataSum === 0) {
        document.getElementById('no-data').style.display = 'block';
        document.getElementById('pieChartExample01').style.display = 'none'
      }
    }
  }
}

Fiddle

11
votes

Use this plugin I slightly modified which checks if each dataset item is zero:

<script>
    Chart.plugins.register({
        afterDraw: function(chart) {
            if (chart.data.datasets[0].data.every(item => item === 0)) {
                let ctx = chart.chart.ctx;
                let width = chart.chart.width;
                let height = chart.chart.height;

                chart.clear();
                ctx.save();
                ctx.textAlign = 'center';
                ctx.textBaseline = 'middle';
                ctx.fillText('No data to display', width / 2, height / 2);
                ctx.restore();
            }
        }
    });
</script>

With this, if all dataset items are 0, it will display No data to display in place of the chart.

-4
votes

You need to set some data in data: [0, 0, 0, 0] It's imposible to display pie graph without any data i try to change only data and all it's good.

...
data: [2, 3, 4, 5]
...

https://jsfiddle.net/myeLq37j/