[Chartjs]-ChartJS: Highlight dataset in a stacked bar chart when hovering over the legend?

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1👍

With the new upcomming release of version 3 you can do this with the setActive elements.

Documentation: https://www.chartjs.org/docs/master/developers/api/#setactiveelementsactiveelements

var options = {
  type: 'bar',
  data: {
    labels: ["Red", "Blue", "Yellow", "Green", "Purple", "Orange"],
    datasets: [{
        label: '# of Votes',
        data: [12, 19, 3, 5, 2, 3],
        borderWidth: 1,
        hoverBackgroundColor: 'green',
      },
      {
        label: '# of Points',
        data: [7, 11, 5, 8, 3, 7],
        borderWidth: 1,
        hoverBackgroundColor: 'red',
      }
    ]
  },
  options: {
    scales: {}
  }
}

var ctx = document.getElementById('chartJSContainer').getContext('2d');
const chart = new Chart(ctx, options);
chart.setActiveElements([{
  datasetIndex: 0,
  index: 1,
}, {
  datasetIndex: 1,
  index: 1,
}]);
<body>
  <canvas id="chartJSContainer" width="600" height="400"></canvas>
  <script src="https://cdnjs.cloudflare.com/ajax/libs/Chart.js/3.0.0-beta.10/chart.js" integrity="sha512-7igYTuENB1pHNsZ/SyzMYrcJAmRCk084yVOsxNNCQAdX1wSYvCeBOgSOMC6wUdKMO76kCJNOpW4jY3UW5CoBnA==" crossorigin="anonymous"></script>
</body>

1👍

Using ChartJS 3 setActiveElements API, you can highlight an entire dataset on legend hover using the following code in options.plugins.legend

onHover: function (event, legendItem) {
    const datasetIndex = legendItem.datasetIndex;
    let elementList = [];
    for (let i = 0; i < this.chart.getDatasetMeta(datasetIndex).data.length; i++) {
            elementList.push({
                'datasetIndex': datasetIndex,
                'index': i,
            });
    }
    this.chart.setActiveElements(elementList);
    this.chart.update();
}

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