React Charts - Server-Side Data Processing

In many cases, you need to process data on the server before a chart displays it. The Chart component supports this scenario.

In this demo, the data source of the Chart loads weather data for a selected month from an OData service. Each time you select a different month in the drop-down menu, the data source sends a new query to the service. To implement this functionality, assign a DataSource object to the Chart's dataSource property.

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TS JS

Backend API

import React from 'react'; import { DataSource } from 'devextreme-react/common/data'; import Chart, { ValueAxis, ArgumentAxis, CommonPaneSettings, Grid, Series, Label, Legend, Size, Border, Tooltip, Export, LoadingIndicator, } from 'devextreme-react/chart'; import SelectBox, { type SelectBoxTypes } from 'devextreme-react/select-box'; import { months, monthLabel } from './data.ts'; const year = 2017; let selectedMonth = 1; const startOfMonthStr = (month: number): string => `${month}/01/${year}`; const endOfMonthStr = (month: number): string => { const nextMonth = (month === 12) ? 1 : month + 1; const nextYear = (month === 12) ? year + 1 : year; const lastDay = new Date(nextYear, nextMonth - 1, 0).getDate(); return `${month}/${lastDay}/${year}`; }; const chartDataSource = new DataSource({ key: 'Date', load: () => { const startVisible = startOfMonthStr(selectedMonth); const endVisible = endOfMonthStr(selectedMonth); const url = 'https://js.devexpress.com/Demos/NetCore/api/TemperatureData' + `?startVisible=${encodeURIComponent(startVisible)}` + `&endVisible=${encodeURIComponent(endVisible)}` + `&startBound=${encodeURIComponent(startVisible)}` + `&endBound=${encodeURIComponent(endVisible)}`; return fetch(url) .then((r) => { if (!r.ok) throw new Error(`Network response fails: ${r.status}`); return r.json(); }) .then((arr) => arr.map((item) => ({ ...item, Temperature: (item.MinTemp + item.MaxTemp) / 2, Date: new Date(item.Date), }))); }, paginate: false, }); function onValueChanged(data: SelectBoxTypes.ValueChangedEvent) { selectedMonth = data.value; chartDataSource.load(); } function customizeLabel(e: { valueText: string; }) { return `${e.valueText}${'&#176C'}`; } function customizeArgumentAxisLabel(e: { value: string | number | Date, valueText: string; }) { return new Date(e.value).getDate().toString(); } function customizeTooltip(arg: { valueText: string; }) { return { text: `${arg.valueText}${'&#176C'}`, }; } function App() { return ( <div id="chart-demo"> <Chart title={`Temperature in Seattle, ${year}`} dataSource={chartDataSource}> <Size height={420} /> <ValueAxis valueType="numeric"> <Grid opacity={0.2} /> <Label customizeText={customizeLabel} /> </ValueAxis> <ArgumentAxis type="discrete"> <Grid visible={true} opacity={0.5} /> <Label customizeText={customizeArgumentAxisLabel} /> </ArgumentAxis> <CommonPaneSettings> <Border visible={true} width={2} top={false} right={false} /> </CommonPaneSettings> <Series argumentField="Date" valueField="Temperature" type="spline" /> <Legend visible={false} /> <Export enabled={true} /> <Tooltip enabled={true} customizeTooltip={customizeTooltip} /> <LoadingIndicator enabled={true} /> </Chart> <div className="action"> <div className="label">Choose a month:</div> <SelectBox id="selectbox" width={150} valueExpr="id" inputAttr={monthLabel} displayExpr="name" items={months} defaultValue={selectedMonth} onValueChanged={onValueChanged} /> </div> </div> ); } export default App;

import React from 'react'; import { DataSource } from 'devextreme-react/common/data'; import Chart, { ValueAxis, ArgumentAxis, CommonPaneSettings, Grid, Series, Label, Legend, Size, Border, Tooltip, Export, LoadingIndicator, } from 'devextreme-react/chart'; import SelectBox from 'devextreme-react/select-box'; import { months, monthLabel } from './data.js'; const year = 2017; let selectedMonth = 1; const startOfMonthStr = (month) => `${month}/01/${year}`; const endOfMonthStr = (month) => { const nextMonth = month === 12 ? 1 : month + 1; const nextYear = month === 12 ? year + 1 : year; const lastDay = new Date(nextYear, nextMonth - 1, 0).getDate(); return `${month}/${lastDay}/${year}`; }; const chartDataSource = new DataSource({ key: 'Date', load: () => { const startVisible = startOfMonthStr(selectedMonth); const endVisible = endOfMonthStr(selectedMonth); const url = 'https://js.devexpress.com/Demos/NetCore/api/TemperatureData' + `?startVisible=${encodeURIComponent(startVisible)}` + `&endVisible=${encodeURIComponent(endVisible)}` + `&startBound=${encodeURIComponent(startVisible)}` + `&endBound=${encodeURIComponent(endVisible)}`; return fetch(url) .then((r) => { if (!r.ok) throw new Error(`Network response fails: ${r.status}`); return r.json(); }) .then((arr) => arr.map((item) => ({ ...item, Temperature: (item.MinTemp + item.MaxTemp) / 2, Date: new Date(item.Date), }))); }, paginate: false, }); function onValueChanged(data) { selectedMonth = data.value; chartDataSource.load(); } function customizeLabel(e) { return `${e.valueText}${'&#176C'}`; } function customizeArgumentAxisLabel(e) { return new Date(e.value).getDate().toString(); } function customizeTooltip(arg) { return { text: `${arg.valueText}${'&#176C'}`, }; } function App() { return ( <div id="chart-demo"> <Chart title={`Temperature in Seattle, ${year}`} dataSource={chartDataSource} > <Size height={420} /> <ValueAxis valueType="numeric"> <Grid opacity={0.2} /> <Label customizeText={customizeLabel} /> </ValueAxis> <ArgumentAxis type="discrete"> <Grid visible={true} opacity={0.5} /> <Label customizeText={customizeArgumentAxisLabel} /> </ArgumentAxis> <CommonPaneSettings> <Border visible={true} width={2} top={false} right={false} /> </CommonPaneSettings> <Series argumentField="Date" valueField="Temperature" type="spline" /> <Legend visible={false} /> <Export enabled={true} /> <Tooltip enabled={true} customizeTooltip={customizeTooltip} /> <LoadingIndicator enabled={true} /> </Chart> <div className="action"> <div className="label">Choose a month:</div> <SelectBox id="selectbox" width={150} valueExpr="id" inputAttr={monthLabel} displayExpr="name" items={months} defaultValue={selectedMonth} onValueChanged={onValueChanged} /> </div> </div> ); } export default App;

import React from 'react'; import ReactDOM from 'react-dom'; import App from './App.tsx'; ReactDOM.render( <App />, document.getElementById('app'), );

export const months = [{ id: 1, name: 'January', }, { id: 2, name: 'February', }, { id: 3, name: 'March', }, { id: 4, name: 'April', }, { id: 5, name: 'May', }, { id: 6, name: 'June', }, { id: 7, name: 'July', }, { id: 8, name: 'August', }, { id: 9, name: 'September', }, { id: 10, name: 'October', }, { id: 11, name: 'November', }, { id: 12, name: 'December', }]; export const monthLabel = { 'aria-label': 'Month' };

import React from 'react'; import ReactDOM from 'react-dom'; import App from './App.js'; ReactDOM.render(<App />, document.getElementById('app'));

export const months = [ { id: 1, name: 'January', }, { id: 2, name: 'February', }, { id: 3, name: 'March', }, { id: 4, name: 'April', }, { id: 5, name: 'May', }, { id: 6, name: 'June', }, { id: 7, name: 'July', }, { id: 8, name: 'August', }, { id: 9, name: 'September', }, { id: 10, name: 'October', }, { id: 11, name: 'November', }, { id: 12, name: 'December', }, ]; export const monthLabel = { 'aria-label': 'Month' };

<!DOCTYPE html> <html lang="en"> <head> <title>DevExtreme Demo</title> <meta http-equiv="X-UA-Compatible" content="IE=edge" /> <meta http-equiv="Content-Type" content="text/html; charset=utf-8" /> <meta name="viewport" content="width=device-width, initial-scale=1.0, maximum-scale=5.0" /> <link rel="stylesheet" type="text/css" href="https://cdn3.devexpress.com/jslib/25.1.6/css/dx.light.css" /> <link rel="stylesheet" type="text/css" href="styles.css" /> <script src="https://cdn.jsdelivr.net/npm/core-js@2.6.12/client/shim.min.js"></script> <script src="https://cdn.jsdelivr.net/npm/systemjs@0.21.3/dist/system.js"></script> <script type="text/javascript" src="config.js"></script> <script type="text/javascript"> System.import("./index.tsx"); </script> </head> <body class="dx-viewport"> <div class="demo-container"> <div id="app"></div> </div> </body> </html>

.action { width: 270px; margin-top: 20px; display: flex; justify-content: space-between; align-items: center; }

In the DataSource, implement the ODataStore. An OData service can include multiple entity collections related to each other, but the ODataStore specifies only one collection. To load multiple collections at once, set the expand property to an array with the additional collection titles. Then, call the postProcess function to process additional data.

Set the paginate property to false to prevent data from partitioning. You can also apply a filter to the received values.

Once you load the data, specify the series type and its nested options (argumentField and valueField), so the component can determine the objects that indicate Chart arguments and values in the data source.

A 1-Click Solution for CRUD Web API Services with Role-based Access Control via EF Core

If you target .NET for your backend API, be sure to check out Web API Service and register your free copy today. The Solution Wizard scaffolds an OData v4 Web API Service (.NET 6+) with integrated authorization & CRUD operations powered by EF Core ORM. You can use OAuth2, JWT or custom authentication strategies alongside tools like Postman or Swagger (OpenAPI) for API testing. The built-in Web API Service also filters out secured server data based on permissions granted to users. Advanced/enterprise functions include audit trail, endpoints to download reports, file attachments, check validation, obtain localized captions, etc.

To use the free Solution Wizard (which creates the Web API Service), run the Universal Component Installer from the DevExpress Download Manager and use our predefined template in Visual Studio 2022+.

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