charts - chartjs 向饼图图例添加百分比

Question

将百分比值添加到图例标签的最简单方法是什么？

我相信它会使用 generateLabels: function (chart) {}，谁能提供一个干净的例子？

Answer 1

似乎没有任何本地方式来显示百分比，但计算它们并将它们设置为标签非常简单:

const data = [1, 2, 3],
  // ref: https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Array/Reduce
  total = data.reduce((accumulator, currentValue) => accumulator + currentValue),
  // ref: https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Array/map
  labels = data.map(value => Math.round((value / total) * 100) + '%');

new Chart(document.getElementById('chart'), {
  type: 'doughnut',
  data: {
    labels: labels,
    datasets: [{
      data: data
    }]
  }
});

<script src="https://cdnjs.cloudflare.com/ajax/libs/Chart.js/2.9.3/Chart.min.js"></script>
<canvas id="chart" height="75"></canvas>

(注意:使用 Math.round() 可能会导致某些数字集相加时不等于 100%。)