在c3js中获取序列的开始和结束位置

<script src="https://cdnjs.cloudflare.com/ajax/libs/c3/0.7.20/c3.min.js"></script>
<link rel="stylesheet" href="https://cdnjs.cloudflare.com/ajax/libs/c3/0.7.20/c3.min.css">

var data = {
  x: 'x',
  columns: [
    ['x', '2022-01-01', '2022-01-02', '2022-01-03', '2022-01-04', '2022-01-05'],
    ['data1', 30, 200, 100, 400, 150],
    ['data2', 50, 20, 10, 40, 15]
  ]
};

var chart = c3.generate({
  bindto: '#chart',
  data: data
});

var targets = chart.internal.data.targets;
var firstTarget = chart.internal.data.getFirstTarget();
var lastTarget = chart.internal.data.getLastTarget();

var firstStartIndex = targets.indexOf(firstTarget);
var lastEndIndex = targets.indexOf(lastTarget) + 1;

console.log("第一个序列的开始位置：" + firstStartIndex);
console.log("最后一个序列的结束位置：" + lastEndIndex);