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Tooltip in EJ2 TypeScript Chart control

3 Feb 202624 minutes to read

The chart displays detailed information about a data point through a tooltip when the mouse pointer moves over the point.

Default tooltip

By default, the tooltip is not visible. You can enable the tooltip by setting the enable property to true and by injecting Tooltip module using Chart.Inject(Tooltip).

import { Chart, StepLineSeries, DateTime, Tooltip } from '@syncfusion/ej2-charts';
import { chartData } from './datasource.ts';
Chart.Inject(StepLineSeries, DateTime, Tooltip);

let chart: Chart = new Chart({
        primaryXAxis: {
            valueType: 'DateTime'
        },
        series: [
            {
                type: 'StepLine',
                dataSource: chartData, xName: 'x', yName: 'y',
                width: 2, name: 'China',
                marker: {
                    visible: true, width: 10, height: 10
                },
            }],
        title: 'Unemployment Rates 1975-2010',
        //Default tooltip for chart
        tooltip: {enable: true}
}, '#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://cdnjs.cloudflare.com/ajax/libs/systemjs/0.19.38/system.js"></script>
    <script src="systemjs.config.js"></script>
<script src="https://cdn.syncfusion.com/ej2/syncfusion-helper.js" type ="text/javascript"></script>
</head>

<body>
    <div id='loader'>Loading....</div>
    <div id='container'>
        <div id='element'></div>
    </div>
     <script id="Unemployment" type="text/x-template">
      <div id='templateWrap'>
     <table style="width:100%;  border: 1px solid black;">
     <tr><th colspan="2" bgcolor="#00FFFF">Unemployment</th></tr>
     <tr><td bgcolor="#00FFFF">${x}:</td><td bgcolor="#00FFFF">${y}</td></tr>
    </table>
    </div>
  </script>
</body>

</html>

Fixed tooltip

By default, the tooltip tracks the mouse movement. You can render the tooltip at a fixed position by using the location property.

import { Chart, StepLineSeries, DateTime, Tooltip } from '@syncfusion/ej2-charts';
import { chartData } from './datasource.ts';
Chart.Inject(StepLineSeries, DateTime, Tooltip);

let chart: Chart = new Chart({
    primaryXAxis: {
        valueType: 'DateTime'
    },
    primaryYAxis: {
        minimum: 0,
        maximum: 20,
        interval: 4
    },
    series: [
        {
            type: 'StepLine',
            dataSource: chartData, xName: 'x', yName: 'y',
            width: 2, name: 'China',
            marker: {
                visible: true, width: 10, height: 10
            },
        }],
    title: 'Unemployment Rates 1975-2010',
    //Default tooltip for chart
    tooltip: { enable: true, location: { x: 120, y: 20 } }
}, '#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://cdnjs.cloudflare.com/ajax/libs/systemjs/0.19.38/system.js"></script>
    <script src="systemjs.config.js"></script>
<script src="https://cdn.syncfusion.com/ej2/syncfusion-helper.js" type ="text/javascript"></script>
</head>

<body>
    <div id='loader'>Loading....</div>
    <div id='container'>
        <div id='element'></div>
    </div>
</body>

</html>

Format the tooltip

By default, the tooltip displays the x- and y-values of a data point. Additional information can be shown by specifying a custom format. For example, the format ${series.name} ${point.x} displays the series name along with the x-value of the data point.

import { Chart, SplineSeries, DateTime, Tooltip } from '@syncfusion/ej2-charts';
import { chartData } from './datasource.ts';
Chart.Inject(SplineSeries, DateTime, Tooltip);

let chart: Chart = new Chart({
        primaryXAxis: {
            valueType: 'DateTime',
        },
        series: [
            {
                type: 'Spline',
                dataSource: chartData, xName: 'x', yName: 'y',
                width: 2, name: 'China',
                marker: {
                    visible: true, width: 10, height: 10
                },
            }
        ],
        title: 'Unemployment Rates 1975-2010',
        tooltip: {
            enable: true,
            //tooltip format for chart
             header: 'Unemployment',
             format: '<b>${point.x} : ${point.y}</b>'
        }
}, '#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://cdnjs.cloudflare.com/ajax/libs/systemjs/0.19.38/system.js"></script>
    <script src="systemjs.config.js"></script>
<script src="https://cdn.syncfusion.com/ej2/syncfusion-helper.js" type ="text/javascript"></script>
</head>

<body>
    <div id='loader'>Loading....</div>
    <div id='container'>
        <div id='element'></div>
    </div>
     <script id="Unemployment" type="text/x-template">
      <div id='templateWrap'>
     <table style="width:100%;  border: 1px solid black;">
     <tr><th colspan="2" bgcolor="#00FFFF">Unemployment</th></tr>
     <tr><td bgcolor="#00FFFF">${x}:</td><td bgcolor="#00FFFF">${y}</td></tr>
    </table>
    </div>
  </script>
</body>

</html>

Tooltip template

Custom HTML content can be rendered in the tooltip by using the template property. The ${x} and ${y} placeholders can be used within the template to display the x- and y-values of the corresponding data point.

import { Chart, StepLineSeries, Legend, Tooltip } from '@syncfusion/ej2-charts';
import { data } from './datasource.ts';
Chart.Inject(StepLineSeries, Legend, Tooltip);

let chart: Chart = new Chart({
        series: [
            {
                type: 'StepLine',
                dataSource: data, xName: 'x', yName: 'y',
                width: 2, name: 'China',
                marker: {
                    visible: true, width: 10, height: 10
                },
            }
        ],
        title: 'Unemployment Rates 1975-2010',
        tooltip: {
            enable: true,
            //tooltip template for chart
            template: '#Unemployment'
        }
}, '#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://cdnjs.cloudflare.com/ajax/libs/systemjs/0.19.38/system.js"></script>
    <script src="systemjs.config.js"></script>
<script src="https://cdn.syncfusion.com/ej2/syncfusion-helper.js" type ="text/javascript"></script>
</head>

<body>
    <div id='loader'>Loading....</div>
    <div id='container'>
        <div id='element'></div>
    </div>
     <script id="Unemployment" type="text/x-template">
      <div id='templateWrap'>
     <table style="width:100%;  border: 1px solid black;">
     <tr><th colspan="2" bgcolor="#00FFFF">Unemployment</th></tr>
     <tr><td bgcolor="#00FFFF">${x}:</td><td bgcolor="#00FFFF">${y}</td></tr>
    </table>
    </div>
  </script>
</body>

</html>

Enable highlight

By setting the enableHighlight property to true, all points in the hovered series are highlighted while the remaining points are dimmed. This behavior improves focus and readability during data analysis.

import { Chart, StepLineSeries, DateTime, Tooltip, Legend } from '@syncfusion/ej2-charts';
import { chartData } from './datasource.ts';
Chart.Inject(StepLineSeries, DateTime, Tooltip, Legend);

let chart: Chart = new Chart({
    primaryXAxis: {
        title: 'Years',
        lineStyle: { width: 0 },
        labelFormat: 'y',
        intervalType: 'Years',
        valueType: 'DateTime',
        edgeLabelPlacement: 'Shift'
    },
    primaryYAxis: {
        title: 'Percentage (%)',
        minimum: 0, 
        maximum: 20, 
        interval: 4,
        labelFormat: '{value}%'
    },
    series: [
        {
            type: 'StepLine',
            dataSource: chartData, xName: 'x', yName: 'y',
            width: 2, name: 'China',
            marker: { visible: true, width: 10, height: 10 }
        },
        {
            type: 'StepLine',
            dataSource: chartData, xName: 'x', yName: 'y1',
            width: 2, name: 'Australia',
            marker: { visible: true, width: 10, height: 10 }
        },
        {
            type: 'StepLine',
            dataSource: chartData, xName: 'x', yName: 'y2',
            width: 2, name: 'Japan',
            marker: { visible: true, width: 10, height: 10 }
        }
    ],
    title: 'Unemployment Rates 1975-2010',
    legendSettings: { visible: true },
    tooltip: { enable: true, enableHighlight: true }
}, '#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://cdnjs.cloudflare.com/ajax/libs/systemjs/0.19.38/system.js"></script>
    <script src="systemjs.config.js"></script>
<script src="https://cdn.syncfusion.com/ej2/syncfusion-helper.js" type ="text/javascript"></script>
</head>

<body>
    <div id='loader'>Loading....</div>
    <div id='container'>
        <div id='element'></div>
    </div>
</body>

</html>

Customize the appearance of tooltip

The appearance of the tooltip can be customized by using the following properties:

  • fill to set the background color
  • border to configure the tooltip border
  • textStyle to customize the tooltip text style

The highlightColor property is used to change the color of a data point when it is highlighted during tooltip interaction.

import { Chart, StepLineSeries, DateTime, Legend, Tooltip } from '@syncfusion/ej2-charts';
import { chartData } from './datasource.ts';
Chart.Inject(StepLineSeries, DateTime, Legend, Tooltip);

let chart: Chart = new Chart({
        primaryXAxis: {
            valueType: 'DateTime',
        },
        //Highlight color for tooltip
        highlightColor: 'red',
        series: [
            {
                type: 'StepLine',
                dataSource: chartData, xName: 'x', yName: 'y',
                width: 2, name: 'China',
                marker: {
                    visible: true, width: 10, height: 10
                },
            }
        ],
        title: 'Unemployment Rates 1975-2010',
        tooltip: {
            enable: true,
            format: '${series.name} ${point.x} : ${point.y}',
            //fill for tooltip
            fill: '#7bb4eb',
            //border for tooltip
            border: {
                width: 2,
                color: 'grey'
            }
        }
}, '#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://cdnjs.cloudflare.com/ajax/libs/systemjs/0.19.38/system.js"></script>
    <script src="systemjs.config.js"></script>
<script src="https://cdn.syncfusion.com/ej2/syncfusion-helper.js" type ="text/javascript"></script>
</head>

<body>
    <div id='loader'>Loading....</div>
    <div id='container'>
        <div id='element'></div>
    </div>
     <script id="Unemployment" type="text/x-template">
      <div id='templateWrap'>
     <table style="width:100%;  border: 1px solid black;">
     <tr><th colspan="2" bgcolor="#00FFFF">Unemployment</th></tr>
     <tr><td bgcolor="#00FFFF">${x}:</td><td bgcolor="#00FFFF">${y}</td></tr>
    </table>
    </div>
  </script>
</body>

</html>

Closest tooltip

The showNearestTooltip property displays the tooltip for the data point nearest to the pointer, even when the pointer is not directly positioned over the point.

import { Chart, StepLineSeries, DateTime, Tooltip, Legend } from '@syncfusion/ej2-charts';
import { chartData } from './datasource.ts';
Chart.Inject(StepLineSeries, DateTime, Tooltip, Legend);

let chart: Chart = new Chart({
    primaryXAxis: {
        title: 'Years',
        lineStyle: { width: 0 },
        labelFormat: 'y',
        intervalType: 'Years',
        valueType: 'DateTime',
        edgeLabelPlacement: 'Shift'
    },
    primaryYAxis: {
        title: 'Percentage (%)',
        minimum: 0, 
        maximum: 20, 
        interval: 4,
        labelFormat: '{value}%'
    },
    series: [
        {
            type: 'StepLine',
            dataSource: chartData, xName: 'x', yName: 'y',
            width: 2, name: 'China',
            marker: { visible: true, width: 10, height: 10 }
        },
        {
            type: 'StepLine',
            dataSource: chartData, xName: 'x', yName: 'y1',
            width: 2, name: 'Australia',
            marker: { visible: true, width: 10, height: 10 }
        },
        {
            type: 'StepLine',
            dataSource: chartData, xName: 'x', yName: 'y2',
            width: 2, name: 'Japan',
            marker: { visible: true, width: 10, height: 10 }
        }
    ],
    title: 'Unemployment Rates 1975-2010',
    legendSettings: { visible: true },
    tooltip: { enable: true, enableHighlight: true , showNearestTooltip: true}
}, '#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://cdnjs.cloudflare.com/ajax/libs/systemjs/0.19.38/system.js"></script>
    <script src="systemjs.config.js"></script>
<script src="https://cdn.syncfusion.com/ej2/syncfusion-helper.js" type ="text/javascript"></script>
</head>

<body>
    <div id='loader'>Loading....</div>
    <div id='container'>
        <div id='element'></div>
    </div>
</body>

</html>

See also