Demo of yAxis.stackLabels.rotation

HTML

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

<script src="https://cdn.jsdelivr.net/npm/@highcharts/controls@0.8.0" type="module"></script>

<figure class="highcharts-figure">
  <div id="container"></div>
</figure>

<div class="highcharts-controls-wrapper">
  <highcharts-controls>
    <highcharts-group header="Update options">
      <highcharts-control type="number" path="yAxis.stackLabels.rotation" value="-45"></highcharts-control>
    </highcharts-group>
  </highcharts-controls>
</div>

CSS

* {
    font-family:
        -apple-system,
        BlinkMacSystemFont,
        "Segoe UI",
        Roboto,
        Helvetica,
        Arial,
        "Apple Color Emoji",
        "Segoe UI Emoji",
        "Segoe UI Symbol",
        sans-serif;
}

.highcharts-figure {
    max-width: 800px;
    margin: 1em auto;
}

.highcharts-controls-wrapper {
    max-width: 800px;
    margin: 1em auto;
    padding: 0 10px;
}

highcharts-controls {
    display: inline-block;
}

TypeScript

Highcharts.chart('container', {
    chart: {
        type: 'column'
    },
    title: {
        text: 'Demo of <em>yAxis.stackLabels.rotation</em>'
    },
    xAxis: {
        categories: [
            'Jan', 'Feb', 'Mar', 'Apr', 'May', 'Jun', 'Jul', 'Aug', 'Sep',
            'Oct', 'Nov', 'Dec'
        ]
    },
    yAxis: {
        stackLabels: {
            enabled: true,
            rotation: -45
        }
    },
    plotOptions: {
        column: {
            stacking: 'normal'
        }
    },
    series: [{
        data: [29.9, 71.5, 106.4, 129.2]
    }, {
        data: [144, 176, 135.6, 148.5]
    }]
});