test.tsx

import React from 'react';
import ReactDOM from 'react-dom/client';
import DocumentViewer from '@txtextcontrol/tx-react-document-viewer';

declare var TXDocumentViewer: any;

const App: React.FC = () => {

    const load = (contentValue: string) => {
        if (TXDocumentViewer) {
            // encode the content to base64
            contentValue = btoa(contentValue);

            // load the document into the viewer
            TXDocumentViewer.loadDocument(contentValue, "loaded.html");
        }
    };

    return <>
        <select onChange={e => load(e.currentTarget.value)}>
            <option>Select a Document</option>
            <option value="Document <strong>#1</strong>">Document 1</option>
            <option value="Document <strong>#2</strong>">Document 2</option>
            <option value="Document <strong>#3</strong>">Document 3</option>
        </select>

        <br />
        <br />

        <DocumentViewer
            width="800px"
            height="500px"
            basePath ="https://backend.textcontrol.com?access-token=O5KVBVClFm7Pus1qESin"
            isSelectionActivated={true}>
        </DocumentViewer>
    </>;
};

const root = ReactDOM.createRoot(document.getElementById('root')!);

root.render(<App />);