mailchimp.js

passport.use(new MailChimpStrategy({
    clientID: config.auth.mailchimpAuth.clientID,
    clientSecret: config.auth.mailchimpAuth.clientSecret,
    callbackURL: config.auth.mailchimpAuth.callbackURL,
    passReqToCallback : true
  },
  function(req, token, refreshToken, profile, done) {
    token = token + '-' + profile.dc; // Append datacenter to token for API calls to work
    // Save and use token for doing Mailchimp API calls
  }
));