Backend API
        
    import React, { useCallback, useState } from 'react';
import FileUploader, { type FileUploaderTypes } from 'devextreme-react/file-uploader';
import ProgressBar from 'devextreme-react/progress-bar';
const allowedFileExtensions = ['.jpg', '.jpeg', '.gif', '.png'];
export default function App() {
  const [isDropZoneActive, setIsDropZoneActive] = useState(false);
  const [imageSource, setImageSource] = useState<string>('');
  const [textVisible, setTextVisible] = useState(true);
  const [progressVisible, setProgressVisible] = useState(false);
  const [progressValue, setProgressValue] = useState(0);
  const onDropZoneEnter = useCallback(({ component, dropZoneElement, event }) => {
    if (dropZoneElement.id === 'dropzone-external') {
      const items = event.originalEvent.dataTransfer.items;
      const currentAllowedFileExtensions = component.option('allowedFileExtensions');
      const draggedFileExtension = `.${items[0].type.replace(/^image\//, '')}`;
      const isSingleFileDragged = items.length === 1;
      const isValidFileExtension = currentAllowedFileExtensions.includes(draggedFileExtension);
      if (isSingleFileDragged && isValidFileExtension) {
        setIsDropZoneActive(true);
      }
    }
  }, [setIsDropZoneActive]);
  const onDropZoneLeave = useCallback((e: FileUploaderTypes.DropZoneLeaveEvent) => {
    if (e.dropZoneElement.id === 'dropzone-external') {
      setIsDropZoneActive(false);
    }
  }, [setIsDropZoneActive]);
  const onUploaded = useCallback((e: FileUploaderTypes.UploadedEvent) => {
    const { file } = e;
    const fileReader = new FileReader();
    fileReader.onload = () => {
      setIsDropZoneActive(false);
      setImageSource(fileReader.result as string);
    };
    fileReader.readAsDataURL(file);
    setTextVisible(false);
    setProgressVisible(false);
    setProgressValue(0);
  }, [setImageSource, setIsDropZoneActive, setTextVisible, setProgressVisible, setProgressValue]);
  const onProgress = useCallback((e: { bytesLoaded: number; bytesTotal: number; }) => {
    setProgressValue((e.bytesLoaded / e.bytesTotal) * 100);
  }, [setProgressValue]);
  const onUploadStarted = useCallback(() => {
    setImageSource('');
    setProgressVisible(true);
  }, [setImageSource, setProgressVisible]);
  return (
    <div className="widget-container flex-box">
      <span>Profile Picture</span>
      <div id="dropzone-external" className={`flex-box ${isDropZoneActive ? 'dropzone-active' : ''}`}>
        {imageSource && <img id="dropzone-image" src={imageSource} alt="" />}
        {textVisible && (
          <div id="dropzone-text" className="flex-box">
            <span>Drag & Drop the desired file</span>
            <span>…or click to browse for a file instead.</span>
          </div>
        )}
        <ProgressBar
          id="upload-progress"
          min={0}
          max={100}
          width="30%"
          showStatus={false}
          visible={progressVisible}
          value={progressValue}
        ></ProgressBar>
      </div>
      <FileUploader
        id="file-uploader"
        dialogTrigger="#dropzone-external"
        dropZone="#dropzone-external"
        multiple={false}
        allowedFileExtensions={allowedFileExtensions}
        uploadMode="instantly"
        uploadUrl="https://js.devexpress.com/Demos/NetCore/FileUploader/Upload"
        visible={false}
        onDropZoneEnter={onDropZoneEnter}
        onDropZoneLeave={onDropZoneLeave}
        onUploaded={onUploaded}
        onProgress={onProgress}
        onUploadStarted={onUploadStarted}
      ></FileUploader>
    </div>
  );
}
    
    import React, { useCallback, useState } from 'react';
import FileUploader from 'devextreme-react/file-uploader';
import ProgressBar from 'devextreme-react/progress-bar';
const allowedFileExtensions = ['.jpg', '.jpeg', '.gif', '.png'];
export default function App() {
  const [isDropZoneActive, setIsDropZoneActive] = useState(false);
  const [imageSource, setImageSource] = useState('');
  const [textVisible, setTextVisible] = useState(true);
  const [progressVisible, setProgressVisible] = useState(false);
  const [progressValue, setProgressValue] = useState(0);
  const onDropZoneEnter = useCallback(
    ({ component, dropZoneElement, event }) => {
      if (dropZoneElement.id === 'dropzone-external') {
        const items = event.originalEvent.dataTransfer.items;
        const currentAllowedFileExtensions = component.option('allowedFileExtensions');
        const draggedFileExtension = `.${items[0].type.replace(/^image\//, '')}`;
        const isSingleFileDragged = items.length === 1;
        const isValidFileExtension = currentAllowedFileExtensions.includes(draggedFileExtension);
        if (isSingleFileDragged && isValidFileExtension) {
          setIsDropZoneActive(true);
        }
      }
    },
    [setIsDropZoneActive],
  );
  const onDropZoneLeave = useCallback(
    (e) => {
      if (e.dropZoneElement.id === 'dropzone-external') {
        setIsDropZoneActive(false);
      }
    },
    [setIsDropZoneActive],
  );
  const onUploaded = useCallback(
    (e) => {
      const { file } = e;
      const fileReader = new FileReader();
      fileReader.onload = () => {
        setIsDropZoneActive(false);
        setImageSource(fileReader.result);
      };
      fileReader.readAsDataURL(file);
      setTextVisible(false);
      setProgressVisible(false);
      setProgressValue(0);
    },
    [setImageSource, setIsDropZoneActive, setTextVisible, setProgressVisible, setProgressValue],
  );
  const onProgress = useCallback(
    (e) => {
      setProgressValue((e.bytesLoaded / e.bytesTotal) * 100);
    },
    [setProgressValue],
  );
  const onUploadStarted = useCallback(() => {
    setImageSource('');
    setProgressVisible(true);
  }, [setImageSource, setProgressVisible]);
  return (
    <div className="widget-container flex-box">
      <span>Profile Picture</span>
      <div
        id="dropzone-external"
        className={`flex-box ${isDropZoneActive ? 'dropzone-active' : ''}`}
      >
        {imageSource && (
          <img
            id="dropzone-image"
            src={imageSource}
            alt=""
          />
        )}
        {textVisible && (
          <div
            id="dropzone-text"
            className="flex-box"
          >
            <span>Drag & Drop the desired file</span>
            <span>…or click to browse for a file instead.</span>
          </div>
        )}
        <ProgressBar
          id="upload-progress"
          min={0}
          max={100}
          width="30%"
          showStatus={false}
          visible={progressVisible}
          value={progressValue}
        ></ProgressBar>
      </div>
      <FileUploader
        id="file-uploader"
        dialogTrigger="#dropzone-external"
        dropZone="#dropzone-external"
        multiple={false}
        allowedFileExtensions={allowedFileExtensions}
        uploadMode="instantly"
        uploadUrl="https://js.devexpress.com/Demos/NetCore/FileUploader/Upload"
        visible={false}
        onDropZoneEnter={onDropZoneEnter}
        onDropZoneLeave={onDropZoneLeave}
        onUploaded={onUploaded}
        onProgress={onProgress}
        onUploadStarted={onUploadStarted}
      ></FileUploader>
    </div>
  );
}
    
    import React from 'react';
import ReactDOM from 'react-dom';
import App from './App.tsx';
ReactDOM.render(
  <App />,
  document.getElementById('app'),
);
    
    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://cdn.jsdelivr.net/npm/',
    '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',
    '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@1.7.6/dist/dx-quill.min.js',
    'devexpress-diagram': 'npm:devexpress-diagram@2.2.24/dist/dx-diagram.js',
    'devexpress-gantt': 'npm:devexpress-gantt@4.1.64/dist/dx-gantt.js',
    'inferno': 'npm:inferno@8.2.3/dist/inferno.min.js',
    'inferno-compat': 'npm:inferno-compat/dist/inferno-compat.min.js',
    'inferno-create-element': 'npm:inferno-create-element@8.2.3/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',
    '@preact/signals-core': 'npm:@preact/signals-core@1.8.0/dist/signals-core.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-react/common': {
      main: 'index.js',
    },
    'devextreme/events/utils': {
      main: 'index',
    },
    'devextreme/common/core/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',
  ],
  babelOptions: {
    sourceMaps: false,
    stage0: true,
    react: true,
  },
};
System.config(window.config);
// eslint-disable-next-line
const useTgzInCSB = ['openai'];
    
    import React from 'react';
import ReactDOM from 'react-dom';
import App from './App.js';
ReactDOM.render(<App />, document.getElementById('app'));
    
    <!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>
    
    #dropzone-external {
  width: 350px;
  height: 350px;
  background-color: rgb(183 183 183 / 10%);
  border-width: 2px;
  border-style: dashed;
  padding: 10px;
  border-color: var(--dx-color-border);
}
#dropzone-external > * {
  pointer-events: none;
}
#dropzone-external.dropzone-active {
  border-style: solid;
  border-color: var(--dx-color-primary);
}
.widget-container > span {
  font-size: 22px;
  font-weight: bold;
  margin-bottom: 16px;
}
#dropzone-image {
  max-width: 100%;
  max-height: 100%;
}
#dropzone-text > span {
  font-weight: 100;
  opacity: 0.5;
}
#upload-progress {
  display: flex;
  margin-top: 10px;
}
.flex-box {
  display: flex;
  flex-direction: column;
  justify-content: center;
  align-items: center;
}
    
                Allowed file extensions: .jpg, .jpeg, .gif, .png
Maximum file size: 4 MB