chart.js折线图不会在图表中显示超出特定点的线

var ctx = document.getElementById('myChart').getContext('2d');
var myChart = new Chart(ctx, {
    type: 'line',
    data: {
        labels: ['January', 'February', 'March', 'April', 'May', 'June', 'July'],
        datasets: [{
            label: 'My Dataset',
            data: [65, 59, null, 80, 81, 56, 55],
            fill: false,
            borderColor: 'rgb(75, 192, 192)',
            tension: 0.1,
            spanGaps: true // 设置spanGaps为true
        }]
    },
    options: {
        // 配置选项
    }
});