Custom aggregate in EJ2 TypeScript Treegrid control

27 Apr 20235 minutes to read

To calculate the aggregate value with your own aggregate functions, use the custom aggregate option. To use custom aggregation, specify the type as Custom, and provide the custom aggregate function in the customAggregate property.

index.ts
index.html
import { TreeGrid, Aggregate } from '@syncfusion/ej2-treegrid';
import { summaryData } from './datasource.ts';
import { getObject, CustomSummaryType } from '@syncfusion/ej2-grids';

let customAggregateFn: CustomSummaryType = (data: Object): number => {
    let sampleData: Object[] = getObject('result', data);
    let countLength: number; countLength = 0;
    sampleData.filter((item: Object) => {
        let data: string = getObject('category', item);
        if (data === 'Frozen seafood') {
            countLength++;
        }
    });
    return countLength;
};

TreeGrid.Inject(Aggregate);

let treeGridObj: TreeGrid = new TreeGrid(
    {
        dataSource: summaryData,
        childMapping: 'subtasks',
        width: 'auto',
        height: 245,
        treeColumnIndex: 1,
        columns: [
            { field: 'category', headerText: 'Category', width: 200 },
            { field: 'units', headerText: 'Total Units', width: 130, type: 'number', textAlign: 'Right' },
            { field: 'unitPrice', headerText: 'Unit Price($)', width: 110, type: 'number', format: 'C2', textAlign: 'Right' },
            { field: 'price', headerText: 'Price($)', width: 110, textAlign: 'Right', type: 'number', format: 'C' },
        ],
        aggregates: [{
            showChildSummary: false,
            columns: [{
                type: 'Custom',
                customAggregate: customAggregateFn,
                columnName: 'category',
                footerTemplate: 'Count of Frozen seafood : ${Custom}'
            }]
        }]
    });
treeGridObj.appendTo('#TreeGrid');
<!DOCTYPE html>
<html lang="en">

<head>
    <title>EJ2 Grid</title>
    <meta charset="utf-8" />
    <meta name="viewport" content="width=device-width, initial-scale=1.0" />
    <meta name="description" content="Typescript Grid Control" />
    <meta name="author" content="Syncfusion" />
    <link href="index.css" rel="stylesheet" />
    <link href="https://cdn.syncfusion.com/ej2/25.1.35/ej2-base/styles/material.css" rel="stylesheet" />
    <link href="https://cdn.syncfusion.com/ej2/25.1.35/ej2-grids/styles/material.css" rel="stylesheet" />
    <link href="https://cdn.syncfusion.com/ej2/25.1.35/ej2-treegrid/styles/material.css" rel="stylesheet" />
    <link href="https://cdn.syncfusion.com/ej2/25.1.35/ej2-buttons/styles/material.css" rel="stylesheet" />
    <link href="https://cdn.syncfusion.com/ej2/25.1.35/ej2-popups/styles/material.css" rel="stylesheet" />
    <link href="https://cdn.syncfusion.com/ej2/25.1.35/ej2-navigations/styles/material.css" rel="stylesheet" />
    <link href="https://cdn.syncfusion.com/ej2/25.1.35/ej2-dropdowns/styles/material.css" rel="stylesheet" />
    <link href="https://cdn.syncfusion.com/ej2/25.1.35/ej2-lists/styles/material.css" rel="stylesheet" />
    <link href="https://cdn.syncfusion.com/ej2/25.1.35/ej2-inputs/styles/material.css" rel="stylesheet" />
    <link href="https://cdn.syncfusion.com/ej2/25.1.35/ej2-calendars/styles/material.css" rel="stylesheet" />
    
    
    
    <link href="https://cdn.syncfusion.com/ej2/25.1.35/ej2-splitbuttons/styles/material.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='TreeGrid'></div>        
    </div>
</body>
</html>

To access the custom aggregate value inside the template, use the key as Custom.