htdocs/samples/axes_x_tick_fit.html

<html>
  <head>
    <link rel="stylesheet" type="text/css" href="../css/c3.css">
  </head>
  <body>
    <div id="chart"></div>

    <script src="https://d3js.org/d3.v5.min.js" charset="utf-8"></script>
    <script src="../js/c3.js"></script>
    <script>
      var chart = c3.generate({
        data: {
          x: 'x',
          columns: [
            ['x', '2013-10-31', '2013-11-30', '2013-12-31', '2014-01-31', '2014-02-28'],
//            ['x', 30, 70, 150, 200, 350],
            ['sample', 30, 200, 100, 400, 150],
            ['sample2', 130, 300, 200, 500, 250]
          ]
        },
        axis : {
          x : {
            type : 'timeseries',
            tick: {
              fit: true
            }
          }
        },
        subchart: {
//          show: true
        }
      });
    </script>
  </body>
</html>