If you have technical questions, please create a support ticket in the DevExpress Support Center.
import React, { useState } from 'react';
import DataSource from 'devextreme/data/data_source';
import {
Chart,
ChartTypes,
ZoomAndPan,
ScrollBar,
ArgumentAxis,
ValueAxis,
Title,
Label,
Font,
Legend,
Series,
Animation,
LoadingIndicator,
} from 'devextreme-react/chart';
const HALFDAY = 43200000;
let packetsLock = 0;
const chartDataSource = new DataSource({
store: [],
sort: 'date',
paginate: false,
});
const wholeRange = {
startValue: new Date(2017, 0, 1),
endValue: new Date(2017, 11, 31),
};
function App() {
const [visualRange, setVisualRange] = useState({
startValue: new Date(2017, 3, 1),
endValue: new Date(2017, 3, 15),
});
const handleChange = (e: ChartTypes.OptionChangedEvent) => {
if (e.fullName === 'argumentAxis.visualRange') {
const stateStart = visualRange.startValue;
const currentStart = e.value.startValue;
if (stateStart.valueOf() !== currentStart.valueOf()) {
setVisualRange(e.value);
}
onVisualRangeChanged(e.value, e.component);
}
};
return (
<Chart
id="chart"
title="Temperature in Toronto (2017)"
dataSource={chartDataSource}
onOptionChanged={handleChange}
>
<ZoomAndPan argumentAxis="pan" />
<ScrollBar visible={true} />
<ArgumentAxis
argumentType="datetime"
visualRangeUpdateMode="keep"
visualRange={visualRange}
wholeRange={wholeRange}
/>
<ValueAxis name="temperature" allowDecimals={false}>
<Title text='Temperature, °C'>
<Font color="#ff950c" />
</Title>
<Label>
<Font color="#ff950c" />
</Label>
</ValueAxis>
<Series
color="#ff950c"
type="rangearea"
argumentField="date"
rangeValue1Field="minTemp"
rangeValue2Field="maxTemp"
name="Temperature range"
/>
<Animation enabled={false} />
<LoadingIndicator backgroundColor="none">
<Font size={14} />
</LoadingIndicator>
<Legend visible={false} />
</Chart>
);
}
const uploadDataByVisualRange = (visualRange, component) => {
const dataSource = component.getDataSource();
const storage = dataSource.items();
const ajaxArgs = {
startVisible: getDateString(visualRange.startValue),
endVisible: getDateString(visualRange.endValue),
startBound: getDateString(storage.length ? storage[0].date : null),
endBound: getDateString(
storage.length ? storage[storage.length - 1].date : null,
),
};
if (
ajaxArgs.startVisible !== ajaxArgs.startBound
&& ajaxArgs.endVisible !== ajaxArgs.endBound
&& !packetsLock
) {
packetsLock += 1;
component.showLoadingIndicator();
getDataFrame(ajaxArgs)
.then((dataFrame) => {
packetsLock -= 1;
const componentStorage = dataSource.store();
dataFrame
.map((i) => ({
date: new Date(i.Date),
minTemp: i.MinTemp,
maxTemp: i.MaxTemp,
}))
.forEach((item) => componentStorage.insert(item));
dataSource.reload();
onVisualRangeChanged(visualRange, component);
})
.catch(() => {
packetsLock -= 1;
dataSource.reload();
});
}
};
const onVisualRangeChanged = (visualRange, component) => {
const items = component.getDataSource().items();
if (
!items.length
|| items[0].date - visualRange.startValue.getTime() >= HALFDAY
|| visualRange.endValue.getTime() - items[items.length - 1].date >= HALFDAY
) {
uploadDataByVisualRange(visualRange, component);
}
};
function getDataFrame(args) {
let params = '?';
params += `startVisible=${args.startVisible}
&endVisible=${args.endVisible}
&startBound=${args.startBound}
&endBound=${args.endBound}`;
return fetch(
`https://js.devexpress.com/Demos/WidgetsGallery/data/temperatureData${params}`,
).then((response) => response.json());
}
function getDateString(dateTime) {
return dateTime ? dateTime.toLocaleDateString('en-US') : '';
}
export default App;
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import React, { useState } from 'react';
import DataSource from 'devextreme/data/data_source';
import {
Chart,
ZoomAndPan,
ScrollBar,
ArgumentAxis,
ValueAxis,
Title,
Label,
Font,
Legend,
Series,
Animation,
LoadingIndicator,
} from 'devextreme-react/chart';
const HALFDAY = 43200000;
let packetsLock = 0;
const chartDataSource = new DataSource({
store: [],
sort: 'date',
paginate: false,
});
const wholeRange = {
startValue: new Date(2017, 0, 1),
endValue: new Date(2017, 11, 31),
};
function App() {
const [visualRange, setVisualRange] = useState({
startValue: new Date(2017, 3, 1),
endValue: new Date(2017, 3, 15),
});
const handleChange = (e) => {
if (e.fullName === 'argumentAxis.visualRange') {
const stateStart = visualRange.startValue;
const currentStart = e.value.startValue;
if (stateStart.valueOf() !== currentStart.valueOf()) {
setVisualRange(e.value);
}
onVisualRangeChanged(e.value, e.component);
}
};
return (
<Chart
id="chart"
title="Temperature in Toronto (2017)"
dataSource={chartDataSource}
onOptionChanged={handleChange}
>
<ZoomAndPan argumentAxis="pan" />
<ScrollBar visible={true} />
<ArgumentAxis
argumentType="datetime"
visualRangeUpdateMode="keep"
visualRange={visualRange}
wholeRange={wholeRange}
/>
<ValueAxis
name="temperature"
allowDecimals={false}
>
<Title text="Temperature, °C">
<Font color="#ff950c" />
</Title>
<Label>
<Font color="#ff950c" />
</Label>
</ValueAxis>
<Series
color="#ff950c"
type="rangearea"
argumentField="date"
rangeValue1Field="minTemp"
rangeValue2Field="maxTemp"
name="Temperature range"
/>
<Animation enabled={false} />
<LoadingIndicator backgroundColor="none">
<Font size={14} />
</LoadingIndicator>
<Legend visible={false} />
</Chart>
);
}
const uploadDataByVisualRange = (visualRange, component) => {
const dataSource = component.getDataSource();
const storage = dataSource.items();
const ajaxArgs = {
startVisible: getDateString(visualRange.startValue),
endVisible: getDateString(visualRange.endValue),
startBound: getDateString(storage.length ? storage[0].date : null),
endBound: getDateString(storage.length ? storage[storage.length - 1].date : null),
};
if (
ajaxArgs.startVisible !== ajaxArgs.startBound
&& ajaxArgs.endVisible !== ajaxArgs.endBound
&& !packetsLock
) {
packetsLock += 1;
component.showLoadingIndicator();
getDataFrame(ajaxArgs)
.then((dataFrame) => {
packetsLock -= 1;
const componentStorage = dataSource.store();
dataFrame
.map((i) => ({
date: new Date(i.Date),
minTemp: i.MinTemp,
maxTemp: i.MaxTemp,
}))
.forEach((item) => componentStorage.insert(item));
dataSource.reload();
onVisualRangeChanged(visualRange, component);
})
.catch(() => {
packetsLock -= 1;
dataSource.reload();
});
}
};
const onVisualRangeChanged = (visualRange, component) => {
const items = component.getDataSource().items();
if (
!items.length
|| items[0].date - visualRange.startValue.getTime() >= HALFDAY
|| visualRange.endValue.getTime() - items[items.length - 1].date >= HALFDAY
) {
uploadDataByVisualRange(visualRange, component);
}
};
function getDataFrame(args) {
let params = '?';
params += `startVisible=${args.startVisible}
&endVisible=${args.endVisible}
&startBound=${args.startBound}
&endBound=${args.endBound}`;
return fetch(`https://js.devexpress.com/Demos/WidgetsGallery/data/temperatureData${params}`).then(
(response) => response.json(),
);
}
function getDateString(dateTime) {
return dateTime ? dateTime.toLocaleDateString('en-US') : '';
}
export default App;
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import React from 'react';
import ReactDOM from 'react-dom';
import App from './App.tsx';
ReactDOM.render(
<App />,
document.getElementById('app'),
);
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window.exports = window.exports || {};
window.config = {
transpiler: 'ts',
typescriptOptions: {
module: 'system',
emitDecoratorMetadata: true,
experimentalDecorators: true,
jsx: 'react',
},
meta: {
'react': {
'esModule': true,
},
'typescript': {
'exports': 'ts',
},
'devextreme/time_zone_utils.js': {
'esModule': true,
},
'devextreme/localization.js': {
'esModule': true,
},
'devextreme/viz/palette.js': {
'esModule': true,
},
'openai': {
'esModule': true,
},
},
paths: {
'npm:': 'https://unpkg.com/',
'bundles:': 'bundles/',
'externals:': 'bundles/externals/',
},
defaultExtension: 'js',
map: {
'ts': 'npm:plugin-typescript@8.0.0/lib/plugin.js',
'typescript': 'npm:typescript@4.2.4/lib/typescript.js',
'jszip': 'npm:jszip@3.10.1/dist/jszip.min.js',
'react': 'npm:react@17.0.2/umd/react.development.js',
'react-dom': 'npm:react-dom@17.0.2/umd/react-dom.development.js',
'prop-types': 'npm:prop-types/prop-types.js',
'whatwg-fetch': 'npm:whatwg-fetch@2.0.4/fetch.js',
'rrule': 'npm:rrule@2.6.4/dist/es5/rrule.js',
'luxon': 'npm:luxon@3.4.4/build/global/luxon.min.js',
'es6-object-assign': 'npm:es6-object-assign',
'devextreme': 'npm:devextreme@link:../../packages/devextreme/artifacts/npm/devextreme/cjs',
'devextreme-react': 'npm:devextreme-react@link:../../packages/devextreme-react/npm/cjs',
'devextreme-quill': 'npm:devextreme-quill@1.7.1/dist/dx-quill.min.js',
'devexpress-diagram': 'npm:devexpress-diagram@2.2.5/dist/dx-diagram.js',
'devexpress-gantt': 'npm:devexpress-gantt@4.1.54/dist/dx-gantt.js',
'@devextreme/runtime': 'npm:@devextreme/runtime@3.0.12',
'inferno': 'npm:inferno@7.4.11/dist/inferno.min.js',
'inferno-compat': 'npm:inferno-compat/dist/inferno-compat.min.js',
'inferno-create-element': 'npm:inferno-create-element@7.4.11/dist/inferno-create-element.min.js',
'inferno-dom': 'npm:inferno-dom/dist/inferno-dom.min.js',
'inferno-hydrate': 'npm:inferno-hydrate/dist/inferno-hydrate.min.js',
'inferno-clone-vnode': 'npm:inferno-clone-vnode/dist/inferno-clone-vnode.min.js',
'inferno-create-class': 'npm:inferno-create-class/dist/inferno-create-class.min.js',
'inferno-extras': 'npm:inferno-extras/dist/inferno-extras.min.js',
'devextreme-cldr-data': 'npm:devextreme-cldr-data@1.0.3',
// SystemJS plugins
'plugin-babel': 'npm:systemjs-plugin-babel@0.0.25/plugin-babel.js',
'systemjs-babel-build': 'npm:systemjs-plugin-babel@0.0.25/systemjs-babel-browser.js',
// Prettier
'prettier/standalone': 'npm:prettier@2.8.8/standalone.js',
'prettier/parser-html': 'npm:prettier@2.8.8/parser-html.js',
},
packages: {
'devextreme': {
defaultExtension: 'js',
},
'devextreme-react': {
main: 'index.js',
},
'devextreme/events/utils': {
main: 'index',
},
'devextreme/localization/messages': {
format: 'json',
defaultExtension: 'json',
},
'devextreme/events': {
main: 'index',
},
'es6-object-assign': {
main: './index.js',
defaultExtension: 'js',
},
},
packageConfigPaths: [
'npm:@devextreme/*/package.json',
'npm:@devextreme/runtime@3.0.12/inferno/package.json',
],
babelOptions: {
sourceMaps: false,
stage0: true,
react: true,
},
};
System.config(window.config);
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import React from 'react';
import ReactDOM from 'react-dom';
import App from './App.js';
ReactDOM.render(<App />, document.getElementById('app'));
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<html lang="en">
<head></head>
<body class="dx-viewport">
<div class="demo-container">
<div id="app"></div>
</div>
</body>
</html>
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#chart {
height: 440px;
}
To implement this functionality, do the following:
-
Configure a data source.
-
Assign a DataSource with an empty store to the Chart dataSource property.
-
Set the sort property to
date
. -
Disable the paginate property to prevent data from partitioning.
-
-
Configure the Chart to support on-demand data loading.
-
Set the visualRangeUpdateMode property to
keep
. -
Specify a loadingIndicator.
-
Specify the initial visualRange.
-
Implement a function that respond to user pan operations and tracks visualRange changes. If a user changed the visual range, initiate a request for additional data.
-
-
Implement functions that load the data.
-
In this demo, Chart displays daily information. If a user pan the Chart left or right more than half a day, additional data starts to load. The
onVisualRangeChanged
initiates this procedure. -
The
uploadDataByVisualRange
function analyzes the starting and ending points of the visual range and the bounds of already loaded data. If necessary, it calls thegetDataFrame
function to obtain new data points. Finally, it reloads the DataSource and saves the current visual range. -
The
getDataFrame
Ajax request gets the new data frame from the server.
-