Chartjs-Chart.js remove label from legend for if dataset values

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The legend filter function can be used for this, if you tell it to hide labels where in the dataset all data is zeros it will update dynamicly, see example:

var options = {
  type: 'line',
  data: {
    labels: ["Red", "Blue", "Yellow", "Green", "Purple", "Orange"],
    datasets: [{
        label: '# of Votes',
        data: [12, 19, 3, 5, 2, 0],
        borderWidth: 1,
        backgroundColor: ["Red", "Blue", "Yellow", "Green", "Purple", "Orange"]
      },
      {
        label: '# of Counts',
        data: [1, 2, 3,4,5,2],
        borderWidth: 1,
        backgroundColor: ["Red", "Blue", "Yellow", "Green", "Purple", "Orange"]
      }
    ]
  },
  options: {
    plugins: {
      legend: {
        labels: {
          filter: (legendItem, chartData) => (!chartData.datasets[legendItem.datasetIndex].data.every(item => item === 0))
        }
      }
    }
  }
}

var ctx = document.getElementById('chartJSContainer').getContext('2d');
const chart = new Chart(ctx, options);

document.getElementById("tt").addEventListener("click", () => {
  chart.data.datasets[1].data = [0, 0, 0, 0, 0, 0];
  chart.update()
});
<body>
  <canvas id="chartJSContainer" width="600" height="400"></canvas>
  <button id="tt">
    change data
  </button>
  <script src="https://cdnjs.cloudflare.com/ajax/libs/Chart.js/3.1.0/chart.js" integrity="sha512-LlFvdZpYhQdASf4aZfSpmyHD6+waYVfJRwfJrBgki7/Uh+TXMLFYcKMRim65+o3lFsfk20vrK9sJDute7BUAUw==" crossorigin="anonymous"></script>
</body>

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