Highcharts test tool

HTML

<script src="https://code.highcharts.com/highcharts.js"></script>
<script src="https://code.highcharts.com/modules/sankey.js"></script>

<div id="container"></div>

CSS

#container {
    min-width: 300px;
    max-width: 800px;
    height: 300px;
    margin: 1em auto;
}

JavaScript

var chart = Highcharts.chart('container', {
    chart: {
        width: 600
    },
    series: [{
        keys: ['from', 'to', 'weight'],
        data: [
            ['A', '1', 9],
            ['B', '1', 3],
            ['A', '2', 5],
            ['B', '2', 5]
        ],
        dataLabels: {
        		formatter: function () {}
        },
        type: 'sankey'
    }]
});

console.log(
    'Data label count',
    chart.container.querySelectorAll('.highcharts-data-label').length
);