Data labels in EJ2 JavaScript Sparkline control

18 Apr 20239 minutes to read

Data labels are used to display values of data points to improve the readability.

Enable data label

To enable data label for sparkline series, provide visible of the dataLabelSettings as following possible values:

All - Enables data label of all points.
Start - Enables data label of the start point.
End - Enables data label of the end point.
High - Enables data label of the high point.
Low - Enables data label of the low point.
Negative - Enables data labels of the negative points.

The following example shows enabling sparkline data label for all points.

index.js
index.html
//Initialize Sparkline component
var sparklineInstance = new ej.charts.Sparkline({
    height: '200px',
    width: '350px',
    axisSettings: {
        minX: -1, maxX: 7, maxY: 7, minY: -1
    },
    fill: 'blue',
    dataSource:   [0, 6, 4, 1, 3, 2, 5],
    // To enable data label for all points
    dataLabelSettings: {
        visible: ['All']
    },
});
//Render initialized Sparkline
sparklineInstance.appendTo("#element");
<!DOCTYPE html><html lang="en"><head>
    <title>Essential JS 2 for Sparkline </title>
    <meta charset="utf-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <meta name="description" content="Essential JS 2 for Sparkline UI Control">
    <meta name="author" content="Syncfusion">
    <link href="index.css" rel="stylesheet">
    <link href="https://cdn.syncfusion.com/ej2/25.1.35/ej2-charts/styles/material.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>
    
    <div id="container" style="margin-top: 15%;">
            <div id="element" align="center"></div>
    </div>


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

Customize data label

Data labels can be customized using the fill, border, opacity, and textStyle. The following code example shows customizing data label border, text color, and fill color.

index.js
index.html
//Initialize Sparkline component
var sparklineInstance = new ej.charts.Sparkline({
    height: '200px',
    width: '350px',
    axisSettings: {
        minX: -1, maxX: 7, maxY: 8, minY: -1
    },
    fill: 'blue',
    dataSource:   [0, 6, 4, 1, 3, 2, 5],
    // To customize data label fill, border, and text color
    dataLabelSettings: {
        visible: ['All'],
        border: { color: 'blue', width: 1},
        fill: 'blue', opacity: 0.4,
        textStyle: {
            color: 'white'
        }
    },
});
//Render initialized Sparkline
sparklineInstance.appendTo("#element");
<!DOCTYPE html><html lang="en"><head>
    <title>Essential JS 2 for Sparkline </title>
    <meta charset="utf-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <meta name="description" content="Essential JS 2 for Sparkline UI Control">
    <meta name="author" content="Syncfusion">
    <link href="index.css" rel="stylesheet">
    <link href="https://cdn.syncfusion.com/ej2/25.1.35/ej2-charts/styles/material.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>
    
    <div id="container" style="margin-top: 15%;">
            <div id="element" align="center"></div>
    </div>


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

Format data label text

The text of data labels can be formatted using the format API in the sparkline dataLabelSettings. By default, data label shows the y-value of point. The following code example shows how to display x and y-values for points.

index.js
index.html
//Initialize Sparkline component
var sparklineInstance = new ej.charts.Sparkline({
    height: '200px',
    width: '500px',
    axisSettings: {
        minX: -1, maxX: 7, maxY: 8, minY: -1
    },
    fill: 'blue',
    valueType: 'Category',
    xName: 'x', yName: 'y',
    dataSource:   [{x: 'Mon', y: 3 },{x: 'Tue', y: 5 },{x: 'Wed', y: 2 },{x: 'Thu', y: 4 },{x: 'Fri', y: 6 },],
    // To enable data label for all points
    dataLabelSettings: {
        format: '${x} : ${y}',
        visible: ['All'],
        border: { color: 'blue', width: 1},
        fill: 'blue', opacity: 0.4,
        textStyle: {
            color: 'white'
        }
    },
});
//Render initialized Sparkline
sparklineInstance.appendTo("#element");
<!DOCTYPE html><html lang="en"><head>
    <title>Essential JS 2 for Sparkline </title>
    <meta charset="utf-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <meta name="description" content="Essential JS 2 for Sparkline UI Control">
    <meta name="author" content="Syncfusion">
    <link href="index.css" rel="stylesheet">
    <link href="https://cdn.syncfusion.com/ej2/25.1.35/ej2-charts/styles/material.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>
    
    <div id="container" style="margin-top: 15%;">
            <div id="element" align="center"></div>
    </div>


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