[SOLVED] React-PDF - expected expression, got '<'

React-PDF - expected expression, got '<'

Bit of a noob question, but I've been following React and React-pdf documentation/examples, but have been stuck at the titular error so far. Here's my code:

// App.js

import './App.css';
import React from 'react';
import ReactDOM from 'react-dom';
import {Page, Document} from 'react-pdf';
import {StyleSheet} from "@react-pdf/renderer";
import samplePDF from "./pdfs/renal.pdf";


// Create styles
const styles = StyleSheet.create({
    page: {
        flexDirection: 'row', backgroundColor: '#E4E4E4'
    }, section: {
        margin: 10, padding: 10, flexGrow: 1
    }
});

function App() {
    return (
        <div>
            <Document file={samplePDF}>
                <Page pageNumber={1} />
            </Document>
        </div>
    )
}

export default App;

// index.js - unchanged from what's provided by create-react-app

import React from 'react';
import ReactDOM from 'react-dom/client';
import './index.css';
import App from './App';
import reportWebVitals from './reportWebVitals';

const root = ReactDOM.createRoot(document.getElementById('root'));
root.render(
  <React.StrictMode>
    <App />
  </React.StrictMode>
);

// If you want to start measuring performance in your app, pass a function
// to log results (for example: reportWebVitals(console.log))
// or send to an analytics endpoint. Learn more: (removed because SO doesn't like shortened links)
reportWebVitals();

<!-- index.html - unchanged from create-react-app, except for the added Babel script which didn't fix the issue -->

<!DOCTYPE html>
<html lang="en">
  <head>
    <meta charset="utf-8" />
    <link rel="icon" href="%PUBLIC_URL%/favicon.ico" />
    <meta name="viewport" content="width=device-width, initial-scale=1" />
    <meta name="theme-color" content="#000000" />
    <meta
      name="description"
      content="Web site created using create-react-app"
    />
    <link rel="apple-touch-icon" href="%PUBLIC_URL%/logo192.png" />
    <!--
      manifest.json provides metadata used when your web app is installed on a
      user's mobile device or desktop. See https://developers.google.com/web/fundamentals/web-app-manifest/
    -->
    <link rel="manifest" href="%PUBLIC_URL%/manifest.json" />
    <!--
      Notice the use of %PUBLIC_URL% in the tags above.
      It will be replaced with the URL of the `public` folder during the build.
      Only files inside the `public` folder can be referenced from the HTML.

      Unlike "/favicon.ico" or "favicon.ico", "%PUBLIC_URL%/favicon.ico" will
      work correctly both with client-side routing and a non-root public URL.
      Learn how to configure a non-root public URL by running `npm run build`.
    -->
    <!-- babel script -->
    <script src="https://unpkg.com/@babel/standalone/babel.min.js"></script>

    <title>React App</title>
  </head>
  <body>
    <noscript>You need to enable JavaScript to run this app.</noscript>
    <div id="root"></div>
    <!--
      This HTML file is a template.
      If you open it directly in the browser, you will see an empty page.

      You can add webfonts, meta tags, or analytics to this file.
      The build step will place the bundled scripts into the <body> tag.

      To begin the development, run `npm start` or `yarn start`.
      To create a production bundle, use `npm run build` or `yarn build`.
    -->
  </body>
</html>

The error appears on the page after I open it - strangely, I can see 'loading pdf' and sometimes 'failed to load PDF' on the page shortly before the error appears. I've seen similar usages in online examples (for example, here) so I'm a bit confused as to what's going wrong.

Solution

I ended up looking in console and discovered the error 'window.pdfjsWorker is undefined'. Adding this code (from this answer) seemed to work:

import {pdfjs} from 'react-pdf';
pdfjs.GlobalWorkerOptions.workerSrc = `//cdnjs.cloudflare.com/ajax/libs/pdf.js/${pdfjs.version}/pdf.worker.js`;```