Legend customization in EJ2 JavaScript Heatmap chart control

18 Apr 20237 minutes to read

You can change the legend label using the legendRender client-side event. You can also hide the legend label using this client-side event.

var heatmapData = [
    [73000, 39000, 26000, 39000, 94000, 0],
    [93000, 58000, 53000, 38000, 26000, 68000],
    [99000, 28000, 22000, 4000, 66000, 9000],
    [14000, 26000, 97000, 69000, 69000, 3000],
    [7000, 46000, 47000, 47000, 88000, 6000],
    [41000, 55000, 73000, 23000, 30000, 79000],
    [56000, 69000, 21000, 86000, 3000, 33000],
    [45000, 7000, 53000, 81000, 95000, 79000],
    [60000, 77000, 74000, 68000, 88000, 51000],
    [25000, 25000, 10000, 12000, 78000, 14000],
    [25000, 56000, 55000, 58000, 12000, 82000],
    [74000, 33000, 88000, 23000, 86000, 59000]];

var legendRender = function (args) {
        if(args.text=='25,000' || args.text=='50,000'|| args.text=='99,000'){
            args.text = args.text.replace(/,/, "");
            args.text = `${parseInt(args.text/1000)}` + "k "+"$";
        } else {
            args.cancel=true;
        }
};

var heatmap = new ej.heatmap.HeatMap({
     titleSettings: {
            text: 'Sales Revenue per Employee (in US$)',
            textStyle: {
                size: '15px',
                fontWeight: '500',
                fontStyle: 'Normal',
                fontFamily: 'Segoe UI'
            }
        },
        xAxis: {
            labels: ['Nancy', 'Andrew', 'Janet', 'Margaret', 'Steven',
            'Michael', 'Robert', 'Laura', 'Anne', 'Paul', 'Karin',   'Mario'],
        },
        yAxis: {
            labels: ['Mon', 'Tues', 'Wed', 'Thurs', 'Fri', 'Sat'],
        },
        cellSettings: {
            showLabel: false,
        },
        showTooltip: true,
        legendRender: legendRender,
        paletteSettings: {
            palette: [
            { value: 0, color: '#C2E7EC' },
            { value: 25000, color: '#AEDFE6' },
            { value: 50000, color: '#9AD7E0' },
            { value: 75000, color: '#72C7D4' },
            { value: 99000, color: '#5EBFCE' },
        ],
            type: 'Gradient'
        },
        dataSource: heatmapData

});
heatmap.appendTo('#element');
<!DOCTYPE html><html lang="en"><head>
    <title>EJ2 HeatMap</title>
    <meta charset="utf-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <meta name="description" content="Typescript UI Controls">
    <meta name="author" content="Syncfusion">
    <link href="index.css" rel="stylesheet">
    
    
<script src="https://cdn.syncfusion.com/ej2/25.1.35/dist/ej2.min.js" type="text/javascript"></script>
<script src="https://cdn.syncfusion.com/ej2/syncfusion-helper.js" type ="text/javascript"></script>
</head>

<body>
    <script id="tooltipTemplate" type="text/x-template">
        <div id='templateWrap'>
            <table style="width:100%;  border: 1px solid black;">      
            <tr><td bgcolor="#00FFFF">${xValue}:</td><td bgcolor="#00FFFF">${yValue}</td><td bgcolor="#00FFFF">${value}</td></tr>
            </table>
        </div>
    </script>
    
    <div id="container">
        <div id="element">
        </div>
    </div>
    <style>
        table,
        th,
        td {
            border: 1px solid rgb(105, 105, 105);
            border-collapse: collapse;
        }
    </style>


<script>
var ele = document.getElementById('container');
if(ele) {
  ele.style.visibility = "visible";
}   
      </script>
<script src="index.js" type="text/javascript"></script>
</body></html>