YuruToot/app/javascript/packs/application.js

import './public-path';
import main from "mastodon/main";

import { start } from '../mastodon/common';
import { loadLocale } from '../mastodon/locales';
import { loadPolyfills } from '../mastodon/polyfills';

start();

loadPolyfills()
  .then(loadLocale)
  .then(main)
  .catch(e => {
    console.error(e);
  });