Unable to fetch access_token from google plus plugin

Ionic Framework ionic-v3
1

When using the cordova-plugin-facebook4 I was able to get the accessToken like below
this.fb.login([‘email’, ‘public_profile’, ‘user_birthday’]).then(res => {
console.log(res.authResponse.accessToken);
}
But the google plus plugin provides me with only the idToken and serverAuthCode. How do I access the API https://www.googleapis.com/oauth2/v1/userinfo?alt=json&access_token=ACCESS_TOKEN using these???