I've built a PERN app and am trying to get it up and running on Heroku. I keep getting the error:

file:///app/Client/index.js:12
<Provider store={store}>
^

SyntaxError: Unexpected token '<'

This is in the index.js file:

import React from 'react';
import ReactDOM from 'react-dom';
import App from './app.js'
import { Provider } from 'react-redux';
import { store } from './store.js';


ReactDOM.render(
    <Provider store={store}>
        <App />
    </Provider>,
    document.getElementById('root')
);

With package.json:

{
  "name": "e-comm2",
  "version": "1.0.0",
  "homepage": "https://pern-e-commerce.herokuapp.com/",
  "description": "",
  "type": "module",
  "main": "Client/index.js",
  "scripts": {
    "test": "jest",
    "build": "webpack",
    "start": "node Client/index.js",
    "dev-start": "webpack-dev-server --mode development --open --hot"
  }
  //dependencies omitted
}

Any help to point me in the right direction would be really appreciated. Thanks