freeCodeCamp/tools/contributor/dashboard-app/client/src/index.js

import React from 'react';
import ReactDOM from 'react-dom';

import './index.css';
import * as serviceWorker from './serviceWorker';
import theme from './theme';

import App from './App';
import { ThemeProvider } from 'styled-components';

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

serviceWorker.unregister();