score:6

Accepted answer

You may see an implementation as a plugin here and below.

// A plugin that hides slices, given their indices, across all datasets.
var hideSlicesPlugin = {
  afterInit: function(chartInstance) {
    // If `hiddenSlices` has been set.
    if (chartInstance.config.data.hiddenSlices !== undefined) {
      // Iterate all datasets.
      for (var i = 0; i < chartInstance.data.datasets.length; ++i) {
        // Iterate all indices of slices to be hidden.
        chartInstance.config.data.hiddenSlices.forEach(function(index) {
          // Hide this slice for this dataset.
          chartInstance.getDatasetMeta(i).data[index].hidden = true;
        });
      }
      chartInstance.update();
    }
  }
};

Chart.pluginService.register(hideSlicesPlugin);

var ctx = document.getElementById("myChart");

var myChart = new Chart(ctx, {
  type: 'pie',
  data: {
    labels: ["Red", "Blue", "Yellow", "Green", "Purple", "Orange"],
    datasets: [{
      data: [15, 1, 1, 1, 45, 1],
      backgroundColor: [
        'rgba(255, 99, 132, 0.2)',
        'rgba(54, 162, 235, 0.2)',
        'rgba(255, 206, 86, 0.2)',
        'rgba(75, 192, 192, 0.2)',
        'rgba(153, 102, 255, 0.2)',
        'rgba(255, 159, 64, 0.2)'
      ],
      borderColor: [
        'rgba(255,99,132,1)',
        'rgba(54, 162, 235, 1)',
        'rgba(255, 206, 86, 1)',
        'rgba(75, 192, 192, 1)',
        'rgba(153, 102, 255, 1)',
        'rgba(255, 159, 64, 1)'
      ],
      borderWidth: 1
    }, {
      data: [5, 1, 25, 10, 5, 1],
      backgroundColor: [
        'rgba(255, 99, 132, 0.2)',
        'rgba(54, 162, 235, 0.2)',
        'rgba(255, 206, 86, 0.2)',
        'rgba(75, 192, 192, 0.2)',
        'rgba(153, 102, 255, 0.2)',
        'rgba(255, 159, 64, 0.2)'
      ],
      borderColor: [
        'rgba(255,99,132,1)',
        'rgba(54, 162, 235, 1)',
        'rgba(255, 206, 86, 1)',
        'rgba(75, 192, 192, 1)',
        'rgba(153, 102, 255, 1)',
        'rgba(255, 159, 64, 1)'
      ],
      borderWidth: 1
    }],
    // Hide the second (index = 1) and the fourth (index = 3) slice.
    hiddenSlices: [1, 3]
  }
});
<script src="https://cdnjs.cloudflare.com/ajax/libs/Chart.js/2.4.0/Chart.min.js"></script>
<canvas id="myChart" width="400" height="400"></canvas>

The slices to be hidden are provided using the hiddenSlices attribute, which should be an array of indices corresponding to existing slices. The slices are hidden across all datasets using the hideSlicesPlugin, if hiddenSlices has been set.

score:2

Update - 17/Nov/2019

Don't do this, at the time I wrote this I was new to ChartJS and Web Development as well and it seems that the solution above already outdated, so I tried to answer with things that works for me. Maybe it's already outdated too, I haven't used ChartJS much since then. I moved to Echarts.

Since @xnakos answer is already outdated, I just wanted to share the same thing can be done easier in the current ChartJS version (2.7.3). Simply set the values to undefined, setting it to other values such as null will leave the legends being seen (or not crossed).

var ctx = document.getElementById("myDoughnut").getContext("2d");
var myChart = new Chart(ctx, {
  type: 'doughnut',
  data: {
    labels: ["Red", "Green", "Blue"],
    datasets: [{
      label: '# of Votes',
      data: [12, 19, undefined],
      // Set this value to undefined
      backgroundColor: [
        '#f87979',
        '#79f879',
        '#7979f8'
      ],
      borderWidth: 5
    }]
  },
  options: {
    tooltips: {
      mode: null
    },
    plugins: {
      datalabels: {
        borderWidth: 5,
        borderColor: "white",
        borderRadius: 8,
        // color: 0,
        font: {
          weight: "bold"
        },
        backgroundColor: "lightgray"
      }
    }
  }
});
<div id="app">
  <div width="400">
    <canvas id="myDoughnut"></canvas>
  </div>
</div>
<script src="https://cdnjs.cloudflare.com/ajax/libs/Chart.js/2.7.3/Chart.min.js"></script>
<script src="https://cdn.jsdelivr.net/npm/chartjs-plugin-datalabels@0.4.0/dist/chartjs-plugin-datalabels.js"></script>

<!-- Made in 21 Nov 2018 -->
<!-- with ChartJS 2.7.3 -->

Here's a link to JSFiddle, for you to play around. http://jsfiddle.net/irfandyjip89/fokbgnvz/5/

However, must be noted, if you're using datasets on Pie/Doughnut, it's better to set it into null. Because one undefined value in any of the dataset will cross the legends.

But if you do set one undefined values on any of the dataset, it will result in the legends being crossed (or strikethrough). EVEN WHEN THERE'S A VALUE ON THE NEXT DATASET.

This means that if you only use one dataset, and you don't want the data being shown in the chart and getting the legends crossed you want to set the values to undefined. Whereas, null values will get you same result without the legends being crossed.

However it's preference on how the Chart should appear, but personally I would want to use undefined values if I would like to cross the legends (usually on one dataset chart)and hide the data, and will use null values if I would like to just hide the data without getting the legends crossed (usually on multiple dataset chart).

If you want to check how it went when playing with multiple datasets, you can check this fiddle http://jsfiddle.net/irfandyjip89/fokbgnvz/19/

P.S. If you're wondering how did I put a label value on the center, it's using a plugin called chartjs-plugin-datalabels

score:2

None of the answers provided here have worked for Chart.js version 3.2.1 (what I am using). Here is what I came up with (and it works):

let ctx = document.getElementById('myChart').getContext('2d');

window.chart = new Chart(ctx, {
  type: 'pie',
  data: {
    labels: ['Red', 'Orange', 'Yellow', 'Green', 'Blue'],
    datasets: [{
      data: [100, 100, 200, 300, 140],
      backgroundColor: ['rgb(255, 99, 132)', 'rgb(255, 159, 64)', 'rgb(255, 205, 86)', 'rgb(75, 192, 192)', 'rgb(54, 162, 235)'],
      hoverOffset: 6,
    }]
  },
  options: {
    layout: { padding: 10 },
    responsive: true,
    maintainAspectRatio: true,
    plugins: {
      title: {
        display: true,
        text: 'Colors - Sample Pie Chart'
      }
    }
  }
});

toggleData('red');

window.chart.render();

function toggleData(txt) {

    let ci = window.chart;
    let legendItems = ci.legend.legendItems;
    let index;
    for (index = 0; index < legendItems.length; ++index) {
        let legendItem = legendItems[index];
        if (legendItem.text.toLowerCase() === txt.toLowerCase()) {
            // let visible = chart.getDataVisibility(index);
            ci.toggleDataVisibility(index);
            ci.update();
            return;
        }
    }
}
/*
Note: Do not style the canvas element. See:
https://github.com/chartjs/Chart.js/issues/9089
*/
#myChartContainer {
  width:400px;
  height:400px;
}
<div id="myChartContainer">
  <canvas id="myChart"></canvas>
</div>

<script src="https://cdn.jsdelivr.net/npm/chart.js@3.2.1/dist/chart.min.js"
        integrity="sha256-uVEHWRIr846/vAdLJeybWxjPNStREzOlqLMXjW/Saeo=" crossorigin="anonymous"></script>

References:

score:4

After creating the chart, you can retrieve its metadata through .getDatasetMeta(index), change the hidden attribute of the desired slice and update the chart as shown in the following code snippet. When the user clicks on the label of the hidden slice, it will become visible again.

const chart = new Chart(document.getElementById('myChart'), {
  type: 'pie',
  data: {
    labels: ['Red', 'Orange', 'Yellow', 'Green', 'Blue'],
    datasets: [{
      data: [100, 100, 200, 300, 140],
      backgroundColor: ['rgb(255, 99, 132)', 'rgb(255, 159, 64)', 'rgb(255, 205, 86)', 'rgb(75, 192, 192)', 'rgb(54, 162, 235)']
    }]
  },
  options: {
    responsive: true,
    maintainAspectRatio: true,
    title: {
      display: true,
      text: 'Colors - Sample Pie Chart'
    }
  }
});

chart.getDatasetMeta(0).data[4].hidden = true;    
chart.update();
<script src="https://cdnjs.cloudflare.com/ajax/libs/Chart.js/2.9.3/Chart.min.js"></script>
<canvas id="myChart" height="150"> </canvas>


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