Google sign-in OAuth2 sample

googleApisClient.js

import { OAuth2Client } from 'google-auth-library';
const p = console.log;

/**
 * this establishes the connection
 * @return { OAuth2Client }
 */
function getOAuth2Client() {
  return new OAuth2Client('YOUR_CLIENT_ID', 'YOUR_CLIENT_SECRET', 'REDIRECT_URL');
}

/**
 * fetch the fresh info with token
 * @param { string } token
 */
async function verifyIdToken(token) {
  try {
    const client = getOAuth2Client();
    const ticket = await client.verifyIdToken({
      idToken: token,
      audience: 'YOUR_CLIENT_ID'
    });
    const payload = ticket.getPayload();
    p('payload', JSON.stringify(payload, null, 2));

    const id = payload.sub;
    return id;
  } catch (e) {
    p(e);
    return null;
  }
}

export { verifyIdToken };