// App.js
import Analytics from '@aws-amplify/analytics';
import Auth from '@aws-amplify/auth';
// ...
const mapObj = f => obj =>
  Object.keys(obj).reduce((acc, key) => ({ ...acc, [key]: f(obj[key]) }), {});
const toArrayOfStrings = value => [`${value}`];
const mapToArrayOfStrings = mapObj(toArrayOfStrings);

async function trackUserId() {
  try {
    const { attributes } = await Auth.currentAuthenticatedUser();
    const userAttributes = mapToArrayOfStrings(attributes);
    Analytics.updateEndpoint({
      address: attributes.email,
      channelType: 'EMAIL',
      optOut: 'NONE',
      userId: attributes.sub,
      userAttributes,
    });
  } catch (error) {
    console.log(error);
  }
}

function App() {
  useEffect(() => {
    trackUserId();
  }, []);
  return // ...