pokemon.trade/app/javascript/packs/frontend.tsx

import 'core-js/stable';
import 'regenerator-runtime/runtime';

import React from 'react';
import {hydrate} from 'react-dom';

document.addEventListener('DOMContentLoaded', (): void => {
  import('../src').then(({default: App}): void => {
    hydrate(<App />, document.querySelector('main[id="app"]'));
  });
});