Virtual scrolling in EJ2 TypeScript Pivot Table component

19 Mar 202420 minutes to read

Virtual Scrolling

Allows to load the large amounts of data without any performance degradation by rendering rows and columns only in the current content viewport. Rest of the aggregated data will be brought into viewport dynamically based on vertical or horizontal scroll position. This feature can be enabled by setting the enableVirtualization property in pivot table to true.

To use the virtual scrolling feature, inject the VirtualScroll module in to the pivot table.

import { PivotView, VirtualScroll, IDataSet } from '@syncfusion/ej2-pivotview';

let data: Function = (count: number) => {
    let result: Object[] = [];
    let dt: number = 0;
    for (let i: number = 1; i < (count + 1); i++) {
        dt++;
        let round: string;
        let toString: string = i.toString();
        if (toString.length === 1) {
            round = '0000' + (i);
        }
        else if (toString.length === 2) {
            round = '000' + i;
        }
        else if (toString.length === 3) {
            round = '00' + i;
        } else if (toString.length === 4) {
            round = '0' + i;
        } else {
            round = toString;
        }
        result.push({
            ProductID: 'PRO-' + round,
            Year: "FY " + (dt + 2013),
            Price: Math.round(Math.random() * 5000) + 5000,
            Sold: Math.round(Math.random() * 80) + 10,
        });
        if (dt / 4 == 1) {
            dt = 0;
        }
    }
    return result;
};

PivotView.Inject(VirtualScroll);
let pivotTableObj: PivotView = new PivotView({
    dataSourceSettings: {
        dataSource: data(1000) as IDataSet[],
        enableSorting: false,
        expandAll: true,
        formatSettings: [{ name: 'Price', format: 'C0' }],
        rows: [{ name: 'ProductID' }],
        columns: [{ name: 'Year' }],
        values: [{ name: 'Price', caption: 'Unit Price' }, { name: 'Sold', caption: 'Unit Sold' }]
    },
    width: '100%',
    height: 350,
    enableVirtualization: true
});

pivotTableObj.appendTo('#PivotTable');
<!DOCTYPE html>
<html lang="en">

<head>
    <title>EJ2 Pivot Grid</title>
    <meta charset="utf-8" />
    <meta name="viewport" content="width=device-width, initial-scale=1.0" />
    <meta name="description" content="Typescript Pivot Grid Control" />
    <meta name="author" content="Syncfusion" />
    <link href="index.css" rel="stylesheet" />
    <link href="https://cdn.syncfusion.com/ej2/26.2.4/ej2-base/styles/material.css" rel="stylesheet" />
    <link href="https://cdn.syncfusion.com/ej2/26.2.4/ej2-buttons/styles/material.css" rel="stylesheet" />
    <link href="https://cdn.syncfusion.com/ej2/26.2.4/ej2-calendars/styles/material.css" rel="stylesheet" />
    <link href="https://cdn.syncfusion.com/ej2/26.2.4/ej2-dropdowns/styles/material.css" rel="stylesheet" />
    <link href="https://cdn.syncfusion.com/ej2/26.2.4/ej2-grids/styles/material.css" rel="stylesheet" />
    <link href="https://cdn.syncfusion.com/ej2/26.2.4/ej2-charts/styles/material.css" rel="stylesheet" />
    <link href="https://cdn.syncfusion.com/ej2/26.2.4/ej2-inputs/styles/material.css" rel="stylesheet" />
    <link href="https://cdn.syncfusion.com/ej2/26.2.4/ej2-lists/styles/material.css" rel="stylesheet" />
    <link href="https://cdn.syncfusion.com/ej2/26.2.4/ej2-navigations/styles/material.css" rel="stylesheet" />
    <link href="https://cdn.syncfusion.com/ej2/26.2.4/ej2-popups/styles/material.css" rel="stylesheet" />
    <link href="https://cdn.syncfusion.com/ej2/26.2.4/ej2-pivotview/styles/material.css" rel="stylesheet" />
    <script src="https://cdnjs.cloudflare.com/ajax/libs/systemjs/0.19.38/system.js"></script>
    <link href="https://maxcdn.bootstrapcdn.com/font-awesome/4.7.0/css/font-awesome.min.css" rel="stylesheet"/>
    <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>
            <div id='PivotTable'></div>
        </div>
    </div>
</body>

</html>

Virtual scrolling with single page mode

When virtual scrolling is enabled, the pivot table renders not only the current view page, but also the previous and next pages by default. This default behavior, however, can cause performance delays when dealing with a large number of rows and columns. This is because the same number of rows and columns from adjacent pages are also processed, resulting in additional computational load. This performance constraint can be avoided by setting the allowSinglePage property to true within the virtualScrollSettings.

Enabling this property causes the pivot table to render only the rows and columns that are relevant to the current view page during virtual scrolling. This optimization significantly improves the performance of the pivot table during initial rendering and when performing UI actions such as drill up/down, sorting, filtering, and more.

import { PivotView, VirtualScroll, IDataSet } from '@syncfusion/ej2-pivotview';
import { pivotData } from './datasource.ts';

PivotView.Inject(VirtualScroll);

let pivotTableObj: PivotView = new PivotView({
    dataSourceSettings: {
        dataSource: pivotData(1000) as IDataSet[],
        enableSorting: false,
        expandAll: true,
        formatSettings: [{ name: 'Price', format: 'C0' }],
        rows: [{ name: 'ProductID' }],
        columns: [{ name: 'Year' }],
        values: [{ name: 'Price', caption: 'Unit Price' }, { name: 'Sold', caption: 'Unit Sold' }]
    },
    width: '100%',
    height: 350,
    enableVirtualization: true,
    virtualScrollSettings: {
        allowSinglePage: true
    }
});
pivotTableObj.appendTo('#PivotTable');
<!DOCTYPE html>
<html lang="en">

<head>
    <title>EJ2 Pivot Grid</title>
    <meta charset="utf-8" />
    <meta name="viewport" content="width=device-width, initial-scale=1.0" />
    <meta name="description" content="Typescript Pivot Grid Control" />
    <meta name="author" content="Syncfusion" />
    <link href="index.css" rel="stylesheet" />
    <link href="https://cdn.syncfusion.com/ej2/26.2.4/ej2-base/styles/material.css" rel="stylesheet" />
    <link href="https://cdn.syncfusion.com/ej2/26.2.4/ej2-buttons/styles/material.css" rel="stylesheet" />
    <link href="https://cdn.syncfusion.com/ej2/26.2.4/ej2-calendars/styles/material.css" rel="stylesheet" />
    <link href="https://cdn.syncfusion.com/ej2/26.2.4/ej2-dropdowns/styles/material.css" rel="stylesheet" />
    <link href="https://cdn.syncfusion.com/ej2/26.2.4/ej2-grids/styles/material.css" rel="stylesheet" />
    <link href="https://cdn.syncfusion.com/ej2/26.2.4/ej2-charts/styles/material.css" rel="stylesheet" />
    <link href="https://cdn.syncfusion.com/ej2/26.2.4/ej2-inputs/styles/material.css" rel="stylesheet" />
    <link href="https://cdn.syncfusion.com/ej2/26.2.4/ej2-lists/styles/material.css" rel="stylesheet" />
    <link href="https://cdn.syncfusion.com/ej2/26.2.4/ej2-navigations/styles/material.css" rel="stylesheet" />
    <link href="https://cdn.syncfusion.com/ej2/26.2.4/ej2-popups/styles/material.css" rel="stylesheet" />
    <link href="https://cdn.syncfusion.com/ej2/26.2.4/ej2-pivotview/styles/material.css" rel="stylesheet" />
    <script src="https://cdnjs.cloudflare.com/ajax/libs/systemjs/0.19.38/system.js"></script>
    <link href="https://maxcdn.bootstrapcdn.com/font-awesome/4.7.0/css/font-awesome.min.css" rel="stylesheet"/>
    <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>
            <div id='PivotTable'></div>
        </div>
    </div>
</body>

</html>

Limitations for virtual scrolling

  • In virtual scrolling, the columnWidth property in gridSettings should be in pixels, and percentage values are not accepted.
  • Resizing columns or setting width to individual columns affects the calculation used to pick the correct page on scrolling.
  • Grouping, which takes additional time to splitting the raw items into the provided format.
  • Date Formatting, which takes additional time to convert date format.
  • Date Formatting with sorting, here additionally full date time format should be framed to perform sorting along with the provided date format which lags the performance.
  • When using OLAP data, subtotals and grand totals are only displayed when measures are bound at the last position in the rows or columns axis. Otherwise, the data from the pivot table will be shown without summary totals.
  • Even if virtual scrolling is enabled, not only is the current view port data retrieved, but also the data for the immediate previous page and the immediate next page. As a result, when the end user scrolls slightly ahead or behind, the next or previous page data is displayed immediately without requiring a refresh. Note: If the pivot table’s width and height are large, the loading data count in the current, previous, and next viewports (pages) will also increase, affecting performance.

Overcoming the browser’s height limitation

You can load millions of records in the Pivot Table by using virtual scrolling, where the pivot table loads and renders rows on-demand while scrolling vertically. As a result, Pivot Table lightens the browser’s load by minimizing the DOM elements and rendering elements visible in the viewport. The height of the table is calculated using the Total Records Count * rowHeight property.

The browser has some maximum pixel height limitations for the scroll bar element. The content placed above the maximum height can’t be scrolled if the element height is greater than the browser’s maximum height limit. The browser height limit affects the virtual scrolling of the pivot table. Even when a large number of records are bound to the pivot table, it can only display the records until the maximum height limit of the browser. Once the browser’s height limit is reached while scrolling, you won’t be able to scroll further to view the remaining records.

This maximum pixel height limitation differs between browsers and is entirely dependent on the browser’s default behavior. So, it is best to set the rowHeight to keep the virtual scroll bar element’s height in the pivot table within the browser’s maximum height limit.

Virtual scrolling for static field list

Virtual scrolling automatically works with “Popup” field list on setting the enableVirtualization property in the Pivot Table to true. Incase of static field list, which act as a separate component, user need to enable enableVirtualization property in the Pivot Table and also pass the report information to pivot table instance via the load event of the field list.

import { PivotView, VirtualScroll, PivotFieldList } from '@syncfusion/ej2-pivotview';

let data: Function = (count: number) => {
    let result: Object[] = [];
    let dt: number = 0;
    for (let i: number = 1; i < (count + 1); i++) {
        dt++;
        let round: string;
        let toString: string = i.toString();
        if (toString.length === 1) {
            round = '0000' + (i);
        }
        else if (toString.length === 2) {
            round = '000' + i;
        }
        else if (toString.length === 3) {
            round = '00' + i;
        } else if (toString.length === 4) {
            round = '0' + i;
        } else {
            round = toString;
        }
        result.push({
            ProductID: 'PRO-' + round,
            Year: "FY " + (dt + 2013),
            Price: Math.round(Math.random() * 5000) + 5000,
            Sold: Math.round(Math.random() * 80) + 10,
        });
        if (dt / 4 == 1) {
            dt = 0;
        }
    }
    return result;
};
PivotView.Inject(VirtualScroll);
let pivotObj: PivotView = new PivotView({
    enginePopulated: () => {
        if (fieldListObj) {
            fieldListObj.update(pivotObj);
        }
    },
    enableVirtualization: true,
    height: 350
});
pivotObj.appendTo('#PivotTable');
let fieldListObj: PivotFieldList = new PivotFieldList({
    dataSourceSettings: {
        dataSource: data(1000) as IDataSet[],
        rows: [{ name: 'ProductID' }],
        columns: [{ name: 'Year' }],
        values: [{ name: 'Price', caption: 'Unit Price' }, { name: 'Sold', caption: 'Unit Sold' }]
    },
    renderMode: 'Fixed',
    load: (): void => {
        this.pivotGridModule = pivotObj;
        //Assigning report to pivot table component.
        pivotObj.dataSourceSettings = fieldListObj.dataSourceSettings;
        //Generating page settings based on pivot table component’s size.
        pivotObj.updatePageSettings(true);
        //Assigning page settings to field list component.
        fieldListObj.pageSettings = pivotObj.pageSettings;
    },
    enginePopulated: (): void => {
        fieldListObj.updateView(pivotObj);
    }
});
fieldListObj.appendTo('#Static_FieldList');
<!DOCTYPE html>
<html lang="en">

<head>
    <title>EJ2 Pivot Grid</title>
    <meta charset="utf-8" />
    <meta name="viewport" content="width=device-width, initial-scale=1.0" />
    <meta name="description" content="Typescript Pivot Grid Control" />
    <meta name="author" content="Syncfusion" />
    <link href="index.css" rel="stylesheet" />
    <link href="https://cdn.syncfusion.com/ej2/26.2.4/ej2-base/styles/material.css" rel="stylesheet" />
    <link href="https://cdn.syncfusion.com/ej2/26.2.4/ej2-buttons/styles/material.css" rel="stylesheet" />
    <link href="https://cdn.syncfusion.com/ej2/26.2.4/ej2-calendars/styles/material.css" rel="stylesheet" />
    <link href="https://cdn.syncfusion.com/ej2/26.2.4/ej2-dropdowns/styles/material.css" rel="stylesheet" />
    <link href="https://cdn.syncfusion.com/ej2/26.2.4/ej2-grids/styles/material.css" rel="stylesheet" />
    <link href="https://cdn.syncfusion.com/ej2/26.2.4/ej2-inputs/styles/material.css" rel="stylesheet" />
    <link href="https://cdn.syncfusion.com/ej2/26.2.4/ej2-lists/styles/material.css" rel="stylesheet" />
    <link href="https://cdn.syncfusion.com/ej2/26.2.4/ej2-navigations/styles/material.css" rel="stylesheet" />
    <link href="https://cdn.syncfusion.com/ej2/26.2.4/ej2-popups/styles/material.css" rel="stylesheet" />
    <link href="https://cdn.syncfusion.com/ej2/26.2.4/ej2-pivotview/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='PivotTable'></div>
        <br />
        <div id='Static_FieldList'></div>
    </div>
</body>

</html>

You can also explore our Virtual Scrolling in Typescript PivotTable that showing a large number of records.

See also