docbrown/app/javascript/packs/Onboarding.jsx

import { h, render } from 'preact';
import { getUserDataAndCsrfToken } from '../chat/util';
import getUnopenedChannels from '../src/utils/getUnopenedChannels';

HTMLDocument.prototype.ready = new Promise(resolve => {
  if (document.readyState !== 'loading') {
    return resolve();
  }
  document.addEventListener('DOMContentLoaded', () => resolve());
  return null;
});

function isUserSignedIn() {
  return (
    document.head.querySelector(
      'meta[name="user-signed-in"][content="true"]',
    ) !== null
  );
}

function renderPage() {
  import('../src/Onboarding')
    .then(({ default: Onboarding }) => {
      let waitingForOnboarding = setInterval(function(){
        if (document.getElementById("main-head-stylesheet")) {
          render(<Onboarding />, document.getElementById('top-bar'))
          clearInterval(waitingForOnboarding);
        }
      }, 3)
    })
    .catch(error => {
      // eslint-disable-next-line no-console
      console.error('Unable to load onboarding', error);
    });
}

document.ready.then(
  getUserDataAndCsrfToken()
    .then(({ currentUser, csrfToken }) => {
      window.currentUser = currentUser;
      window.csrfToken = csrfToken;

      getUnopenedChannels();

      if (isUserSignedIn() && !currentUser.saw_onboarding) {
        renderPage();
      }
    })
    .catch(error => {
      // eslint-disable-next-line no-console
      console.error('Error getting user and CSRF Token', error);
    }),
);