Chart.js Pie custom legend

Simple pie chart demo implementation.

by beaver71

HTML

<script src="https://cdnjs.cloudflare.com/ajax/libs/Chart.js/2.3.0-rc.1/Chart.js"></script>
<div class="container">
  <h2>Chart.js — Pie Chart Demo</h2>
  <div>
    <div id="legend"></div>
    <canvas id="myChart"></canvas>
  </div>
</div>

CSS

.container {
  width: 80%;
  margin: 15px auto;
}

[class$="-legend"] {
  list-style: none;
  cursor: pointer;
  padding-left: 0;
}

[class$="-legend"] li {
  display: inline-block;
  padding: 0 5px;
}

[class$="-legend"] li.hidden {
  text-decoration: line-through;
}

[class$="-legend"] li span {
  border-radius: 5px;
  display: inline-block;
  height: 10px;
  margin-right: 10px;
  width: 10px;
}

JavaScript

var ctx = document.getElementById("myChart").getContext('2d');
var chart = new Chart(ctx, {
  type: 'pie',
  data: {
    labels: ["Green", "Blue", "Gray", "Purple", "Yellow", "Red", "Black"],
    datasets: [{
      backgroundColor: [
        "#2ecc71",
        "#3498db",
        "#95a5a6",
        "#9b59b6",
        "#f1c40f",
        "#e74c3c",
        "#34495e"
      ],
      data: [12, 19, 3, 17, 28, 24, 7]
    }]
  },
  options: {
    legend: {
      display: false
    },
  }
});

var myLegendContainer = document.getElementById("legend");
// generate HTML legend
myLegendContainer.innerHTML = chart.generateLegend();
// bind onClick event to all LI-tags of the legend
var legendItems = myLegendContainer.getElementsByTagName('li');
for (var i = 0; i < legendItems.length; i += 1) {
  legendItems[i].addEventListener("click", legendClickCallback, false);
}

function legendClickCallback(event) {
  event = event || window.event;

  var target = event.target || event.srcElement;
  while (target.nodeName !== 'LI') {
    target = target.parentElement;
  }
  var parent = target.parentElement;
  var chartId = parseInt(parent.classList[0].split("-")[0], 10);
  var chart = Chart.instances[chartId];
  var index = Array.prototype.slice.call(parent.children).indexOf(target);
  var meta = chart.getDatasetMeta(0);
  console.log(index);
	var item = meta.data[index];

  if (item.hidden === null || item.hidden === false) {
    item.hidden = true;
    target.classList.add('hidden');
  } else {
    target.classList.remove('hidden');
    item.hidden = null;
  }
  chart.update();
}