mastodon/app/javascript/packs/application.js

import loadPolyfills from '../mastodon/load_polyfills';

// import default stylesheet with variables
require('font-awesome/css/font-awesome.css');
import 'styles/application';

require.context('../images/', true);

loadPolyfills().then(() => {
  require('../mastodon/main').default();
}).catch(e => {
  console.error(e);
});