Data labels in EJ2 JavaScript Chart control

22 Aug 202424 minutes to read

Data label can be added to a chart series by enabling the visible option in the dataLabel. By default, the labels will arrange smartly without overlapping.

index.js
index.html
var chartData = [
    { x: new Date(2016, 0, 1), y: -7.1 }, { x: new Date(2016, 1, 1), y: -3.7 },
    { x: new Date(2016, 2, 1), y: 0.8 }, { x: new Date(2016, 3, 1), y: 6.3 },
    { x: new Date(2016, 4, 1), y: 13.3 }, { x: new Date(2016, 5, 1), y: 18.0 },
    { x: new Date(2016, 6, 1), y: 19.8 }, { x: new Date(2016, 7, 1), y: 18.1 },
    { x: new Date(2016, 8, 1), y: 13.1 }, { x: new Date(2016, 9, 1), y: 4.1 },
    { x: new Date(2016, 10, 1), y: -3.8 }, { x: new Date(2016, 11, 1), y: -6.8 }
];
var chart = new ej.charts.Chart({
        primaryXAxis: {
            title: 'Months',
            valueType: 'DateTime', labelFormat: 'yMMM',
            edgeLabelPlacement: 'Shift'
        },
        primaryYAxis:
        {
            title: 'Temperature (Celsius)',
            minimum: -20, maximum: 20, interval: 10,
            edgeLabelPlacement: 'Shift',
            labelFormat: '{value}°C'
        },
        series: [
            {
                type: 'Line', name: 'Warmest', width: 2,
                dataSource: chartData, xName: 'x', yName: 'y',
                marker: {
                    visible: true,
                    height: 10, width: 10,
                    shape: 'Pentagon',
                    //Data label for chart series
                    dataLabel: { visible: true }
                }
            }
        ],
        title: 'Alaska Weather Statistics - 2016'
}, '#element');
<!DOCTYPE html><html lang="en"><head>
    <title>EJ2 Animation</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/ej2/27.2.2/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">
        <div id="element"></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>

Note: To use data label feature, we need to inject DataLabel using Chart.Inject(DataLabel) method.

Position

Using position property, you can place the label either on Top, Middle,Bottom or Outer (outer is applicable for column and bar type series).

index.js
index.html
var chartData = [
    { x: 'Jan', y: -7.1 }, { x: 'Feb', y: -3.7 },
    { x: 'Mar', y: 2 }, { x: 'Apr', y: 6.3 },
    { x: 'May', y: 13.3 }, { x: 'Jun', y: 18.0 },
    { x: 'Jul', y: 19.8 }, { x: 'Aug', y: 18.1 },
    { x: 'Sep', y: 13.1 }, { x: 'Oct', y: 4.1 },
    { x: 'Nov', y: -3.8 }, { x: 'Dec', y: -6.8 }
];
var chart = new ej.charts.Chart({
        primaryXAxis: {
            title: 'Months',
            valueType: 'Category'
        },
        primaryYAxis:
        {
            title: 'Temperature (Celsius)',
            minimum: -20, maximum: 25, interval: 5,
            edgeLabelPlacement: 'Shift',
            labelFormat: '{value}°C'
        },
        series: [
            {
                type: 'Column', name: 'Warmest',
                dataSource: chartData, xName: 'x', yName: 'y',
                marker: {
                    visible: true,
                    height: 10, width: 10,
                    shape: 'Pentagon',
                    //Data label position as middle
                    dataLabel: { visible: true, position: 'Middle' }
                }
            }
        ],
        title: 'Alaska Weather Statistics - 2016'
}, '#element');
<!DOCTYPE html><html lang="en"><head>
    <title>EJ2 Animation</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/ej2/27.2.2/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">
        <div id="element"></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>

Note: The position Outer is applicable for column and bar type series.

Data Label Template

Label content can be formatted by using the template option. Inside the template, you can add the placeholder text ${point.x} and ${point.y} to display corresponding data points x & y value. Using template property, you can set data label template in chart.

index.js
index.html
var chartData = [
    { x: 'Jan', y: -7.1 }, { x: 'Feb', y: -3.7 },
    { x: 'Mar', y: 2 }, { x: 'Apr', y: 6.3 },
    { x: 'May', y: 13.3 }, { x: 'Jun', y: 18.0 },
    { x: 'Jul', y: 19.8 }, { x: 'Aug', y: 18.1 },
    { x: 'Sep', y: 13.1 }, { x: 'Oct', y: 4.1 },
    { x: 'Nov', y: -3.8 }, { x: 'Dec', y: -6.8 }
];
var chart = new ej.charts.Chart({
        primaryXAxis: {
            title: 'Months',
            valueType: 'Category'
        },
        primaryYAxis:
        {
            title: 'Temperature (Celsius)',
            minimum: -20, maximum: 25, interval: 5,
            edgeLabelPlacement: 'Shift',
            labelFormat: '{value}°C'
        },
        series: [
            {
                type: 'Column', name: 'Warmest',
                dataSource: chartData, xName: 'x', yName: 'y',
                marker: {
                    visible: true,
                    height: 10, width: 10,
                    shape: 'Pentagon',
                    //Data label position as middle
                    dataLabel: { visible: true, position: 'Middle', margin:{ left:5, right:5, top:5, bottom:5 } }
                }
            }
        ],
        title: 'Alaska Weather Statistics - 2016'
}, '#element');
<!DOCTYPE html><html lang="en"><head>
    <title>EJ2 Animation</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/ej2/27.2.2/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">
        <div id="element"></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>

Text Mapping

Text from the data source can be mapped using name property.

index.js
index.html
var chartData = [
    { x: 'Jan', y: -7.1 }, { x: 'Feb', y: -3.7 },
    { x: 'Mar', y: 2 }, { x: 'Apr', y: 6.3 },
    { x: 'May', y: 13.3 }, { x: 'Jun', y: 18.0 },
    { x: 'Jul', y: 19.8 }, { x: 'Aug', y: 18.1 },
    { x: 'Sep', y: 13.1 }, { x: 'Oct', y: 4.1 },
    { x: 'Nov', y: -3.8 }, { x: 'Dec', y: -6.8 }
];
var chart = new ej.charts.Chart({
        primaryXAxis: {
            title: 'Months',
            valueType: 'Category'
        },
        primaryYAxis:
        {
            title: 'Temperature (Celsius)',
            minimum: -20, maximum: 25, interval: 5,
            edgeLabelPlacement: 'Shift',
            labelFormat: '{value}°C'
        },
        series: [
            {
                type: 'Column', name: 'Warmest',
                dataSource: chartData, xName: 'x', yName: 'y',
                marker: {
                    visible: true,
                    height: 10, width: 10,
                    shape: 'Pentagon',
                    //Data label position as middle
                    dataLabel: { visible: true, position: 'Middle' }
                }
            }
        ],
        title: 'Alaska Weather Statistics - 2016'
}, '#element');
<!DOCTYPE html><html lang="en"><head>
    <title>EJ2 Animation</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/ej2/27.2.2/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">
        <div id="element"></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 for the chart can be formatted using format property. You can use the global formatting options, such as ‘n’, ‘p’, and ‘c’.

index.js
index.html
var chartData = [
    { x: new Date(2016, 0, 1), y: -7 }, { x: new Date(2016, 1, 1), y: -3 },
    { x: new Date(2016, 2, 1), y: 8 }, { x: new Date(2016, 3, 1), y: 6 },
    { x: new Date(2016, 4, 1), y: 13 }, { x: new Date(2016, 5, 1), y: 18 },
    { x: new Date(2016, 6, 1), y: 19 }, { x: new Date(2016, 7, 1), y: 18 },
    { x: new Date(2016, 8, 1), y: 13 }, { x: new Date(2016, 9, 1), y: 4 },
    { x: new Date(2016, 10, 1), y: -3 }, { x: new Date(2016, 11, 1), y: -6 }
];
var chart = new ej.charts.Chart({
        primaryXAxis: {
            title: 'Months',
            valueType: 'DateTime', labelFormat: 'yMMM',
            edgeLabelPlacement: 'Shift'
        },
        primaryYAxis:
        {
            title: 'Temperature (Celsius)',
            minimum: -20, maximum: 20, interval: 10,
            edgeLabelPlacement: 'Shift',
            labelFormat: '{value}°C'
        },
        series: [
            {
                type: 'Line', name: 'Warmest', width: 2,
                dataSource: chartData, xName: 'x', yName: 'y',
                marker: {
                    visible: true,
                    height: 10, width: 10,
                    shape: 'Pentagon',isFilled: true,
                    //Data label for chart series
                    dataLabel: { visible: true , format:"n2"}
                }
            }
        ],
        title: 'Alaska Weather Statistics - 2016'
}, '#element');
<!DOCTYPE html><html lang="en"><head>
    <title>EJ2 Animation</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/ej2/27.2.2/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">
        <div id="element"></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>

Value	Format	Resultant Value	Description
1000	n1	1000.0	The number is rounded to 1 decimal place.
1000	n2	1000.00	The number is rounded to 2 decimal places.
1000	n3	1000.000	The number is rounded to 3 decimal place.
0.01	p1	1.0%	The number is converted to percentage with 1 decimal place.
0.01	p2	1.00%	The number is converted to percentage with 2 decimal place.
0.01	p3	1.000%	The number is converted to percentage with 3 decimal place.
1000	c1	$1000.0	The currency symbol is appended to number and number is rounded to 1 decimal place.
1000	c2	$1000.00	The currency symbol is appended to number and number is rounded to 2 decimal place.

Margin

margin for data label can be applied to using left, right, bottom and top properties.

index.js
index.html
var chartData = [
    { x: 'Jan', y: -7.1 }, { x: 'Feb', y: -3.7 },
    { x: 'Mar', y: 2 }, { x: 'Apr', y: 6.3 },
    { x: 'May', y: 13.3 }, { x: 'Jun', y: 18.0 },
    { x: 'Jul', y: 19.8 }, { x: 'Aug', y: 18.1 },
    { x: 'Sep', y: 13.1 }, { x: 'Oct', y: 4.1 },
    { x: 'Nov', y: -3.8 }, { x: 'Dec', y: -6.8 }
];
var chart = new ej.charts.Chart({
        primaryXAxis: {
            title: 'Months',
            valueType: 'Category'
        },
        primaryYAxis:
        {
            title: 'Temperature (Celsius)',
            minimum: -20, maximum: 25, interval: 5,
            edgeLabelPlacement: 'Shift',
            labelFormat: '{value}°C'
        },
        series: [
            {
                type: 'Column', name: 'Warmest',
                dataSource: chartData, xName: 'x', yName: 'y',
                marker: {
                    visible: true,
                    height: 10, width: 10,
                    shape: 'Pentagon',
                    //Data label position as middle
                    dataLabel: { visible: true, position: 'Middle', margin:{ left:5, right:5, top:5, bottom:5 } }
                }
            }
        ],
        title: 'Alaska Weather Statistics - 2016'
}, '#element');
<!DOCTYPE html><html lang="en"><head>
    <title>EJ2 Animation</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/ej2/27.2.2/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">
        <div id="element"></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>

Customization

stroke and border of data label can be customized using fill and border properties. Rounded corners can be customized using rx and ry properties.

index.js
index.html
var chartData = [
    { x: 'Jan', y: -7.1 }, { x: 'Feb', y: -3.7 },
    { x: 'Mar', y: 2 }, { x: 'Apr', y: 6.3 },
    { x: 'May', y: 13.3 }, { x: 'Jun', y: 18.0 },
    { x: 'Jul', y: 19.8 }, { x: 'Aug', y: 18.1 },
    { x: 'Sep', y: 13.1 }, { x: 'Oct', y: 4.1 },
    { x: 'Nov', y: -3.8 }, { x: 'Dec', y: -6.8 }
];
var chart = new ej.charts.Chart({
        primaryXAxis: {
            title: 'Months',
            valueType: 'Category'
        },
        primaryYAxis:
        {
            title: 'Temperature (Celsius)',
            minimum: -20, maximum: 25, interval: 5,
            edgeLabelPlacement: 'Shift',
            labelFormat: '{value}°C'
        },
        series: [
            {
                type: 'Column', name: 'Warmest',
                dataSource: chartData, xName: 'x', yName: 'y',
                marker: {
                    visible: true,
                    height: 10, width: 10,
                    shape: 'Pentagon',
                    //Data label position as middle
                    dataLabel: { visible: true, position: 'Middle', margin:{ left:5, right:5, top:5, bottom:5 } }
                }
            }
        ],
        title: 'Alaska Weather Statistics - 2016'
}, '#element');
<!DOCTYPE html><html lang="en"><head>
    <title>EJ2 Animation</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/ej2/27.2.2/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">
        <div id="element"></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>

Note: rx and ry properties requires border values not to be null.

Customizing Specific Point

You can also customize the specific marker and label using pointRender and textRender event. pointRender event allows you to change the shape, color and border for a point, whereas the textRender event allows you to change the text for the point.

index.js
index.html
var chartData = [
    { x: 'Jan', y: -7.1 }, { x: 'Feb', y: -3.7 },
    { x: 'Mar', y: 2 }, { x: 'Apr', y: 6.3 },
    { x: 'May', y: 13.3 }, { x: 'Jun', y: 18.0 },
    { x: 'Jul', y: 19.8 }, { x: 'Aug', y: 18.1 },
    { x: 'Sep', y: 13.1 }, { x: 'Oct', y: 4.1 },
    { x: 'Nov', y: -3.8 }, { x: 'Dec', y: -6.8 }
];
var chart = new ej.charts.Chart({
    primaryXAxis: {
        title: 'Months',
        valueType: 'Category'
    },
    primaryYAxis:
    {
        title: 'Temperature (Celsius)',
        minimum: -20, maximum: 25, interval: 5,
        edgeLabelPlacement: 'Shift',
        labelFormat: '{value}°C'
    },
    series: [
        {
            type: 'Line', name: 'Warmest', width: 2,
            dataSource: chartData, xName: 'x', yName: 'y',
            marker: {
                visible: true,
                height: 10, width: 10,
                shape: 'Pentagon',
                dataLabel: { visible: true }
            }
        }
    ],
    title: 'Alaska Weather Statistics - 2016',
    // pointRender event for chart
    pointRender: (args) => {
        if (args.point.index === 6) {
            args.fill = 'red'
        }
    },
    textRender: (args) => {
        if (args.point.index === 6) {
            args.text = 'Maximum Temperature';
            args.color = 'red';
        }
    }
}, '#element');
<!DOCTYPE html><html lang="en"><head>
    <title>EJ2 Animation</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/ej2/27.2.2/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">
        <div id="element"></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>

Show percentage based on each series points

You can calculate the percentage value based on the sum for each series using the seriesRender and textRender events in the chart. In seriesRender calculate the sum of each series y values and In textRender calculate percentage value based on the sum value and modify the text.

index.js
index.html
var total = [];

var chart = new ej.charts.Chart({
    //Initializing Primary X Axis
    primaryXAxis: {
        valueType: 'Category', interval: 1, majorGridLines: { width: 0 }
    },
    chartArea: { border: { width: 0 } },
    //Initializing Primary X Axis
    primaryYAxis: {
        majorGridLines: { width: 0 },
        majorTickLines: { width: 0 }, lineStyle: { width: 0 }, labelStyle: { color: 'transparent' }
    },
    //Initializing Chart Series
    series: [
        {
            type: 'Column', xName: 'x', width: 2, yName: 'y', name: 'Gold',
            dataSource: [{ x: 'USA', y: 46 }, { x: 'GBR', y: 27 }, { x: 'CHN', y: 26 }],
            marker: { dataLabel: { visible: true, position: 'Top', font: { fontWeight: '600', color:'#ffffff' } } }
        },
        {
            type: 'Column', xName: 'x', width: 2, yName: 'y', name: 'Silver',
            dataSource: [{ x: 'USA', y: 37 }, { x: 'GBR', y: 23 }, { x: 'CHN', y: 18 }],
            marker: { dataLabel: { visible: true, position: 'Top', font: { fontWeight: '600', color:'#ffffff' } } }
        },
        {
            type: 'Column', xName: 'x', width: 2, yName: 'y', name: 'Bronze',
            dataSource: [{ x: 'USA', y: 38 }, { x: 'GBR', y: 17 }, { x: 'CHN', y: 26 }],
            marker: { dataLabel: { visible: true, position: 'Top', font: { fontWeight: '600', color:'#ffffff' } } }
        }
    ],
    //Initializing Chart Title
    title: 'Olympic Medal Counts - RIO', tooltip: { enable: true },
    width: ej.base.Browser.isDevice ? '100%' : '60%',
    seriesRender: function(args) {
        for (var i = 0; i < args.data.length; i++) {
          if (!total[args.data[i].x]) total[args.data[i].x] = 0;
          total[args.data[i].x] += parseInt(args.data[i].y);
        }
      },
    textRender: function(args) {
        var percentage = (parseInt(args.text) / total[args.point.x]) * 100;
        percentage = percentage % 1 === 0 ? percentage : percentage.toFixed(2);
        args.text = percentage + '%';
     },

});
chart.appendTo('#element');
<!DOCTYPE html><html lang="en"><head>
    <title>EJ2 Animation</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/ej2/27.2.2/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">
        <div id="element"></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>