Demo of legend.symbolRadius

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/[email protected]" 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="legend.symbolRadius" value="3" min="0" max="8"></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>legend.symbolRadius</em>'
    },
    legend: {
        symbolRadius: 3
    },
    series: [{
        data: [6, 4, 2],
        name: 'First'
    }, {
        data: [7, 3, 2],
        name: 'Second'
    }, {
        data: [9, 4, 8],
        name: 'Third'
    }, {
        data: [1, 2, 6],
        name: 'Fourth'
    }]
});