ChartJS 如何设置X轴的最大标签？

const months = ['Jan', 'Feb', 'Mar', 'Apr', 'May', 'Jun', 'Jul', 'Aug', 'Sep', 'Oct', 'Nov', 'Dec'];
const years = [2016, 2017, 2018];

const labels = [];
const dataSet = [];
years.forEach((year, index) => {
  months.forEach((month, monthIndex) => {
    const date = moment(`${month} ${year}`, "MMM YYYY").format('YYYY-MM-DD');
    labels.push(date);
    dataSet.push({
      x: date,
      y: (monthIndex + 12) * (index + 1)
    });
  });
});

var data = {
  labels: labels,
  datasets: [{
    pointRadius: 0,
    label: "Positive",
    lineTension: 0,
    data: dataSet,
    borderWidth: 1,
    backgroundColor: "rgba(0, 255, 0, 0.5)"
  }]
};
var options = {
  scales: {
    xAxes: [{
      type: "time",
      distribution: 'series',
      time: {
        min: "2017-01-01",
        max: "2017-12-01",
        displayFormats: {
          day: 'MMM YY'
        }
      },
      ticks: {
        source: "labels"
      },
      gridLines: {
        display: false
      }
    }]
  }
};

var ctx = document.getElementById("myChart").getContext("2d");

var myBarChart = new Chart(ctx, {
  type: "bar",
  data: data,
  options: options
});

<script src="https://cdnjs.cloudflare.com/ajax/libs/moment.js/2.23.0/moment.min.js"></script>
<script src="https://cdnjs.cloudflare.com/ajax/libs/Chart.js/2.7.3/Chart.min.js"></script>
<canvas id="myChart" width="300" height="100"></canvas>