In the same way, we can configure Google authentication in our application; just add the following code into the authWithGoogle() method, and it will open the popup for login with Google:

 authWithGoogle(){
 console.log("Google");      
 googleProvider.addScope('profile');
 googleProvider.addScope('email');
 firebaseApp.auth().signInWithPopup(googleProvider).then((result,error)=>{
   if(error){
     console.log("unable to sign in with google");
    }
   else{
     this.setState({redirect:true,data:result.user})
   }}).catch((error)=>{
        ToastDanger(error.message);
     })
}

As you can see, I have added the additional OAuth 2.0 scopes that we want to request from the auth provider. To add a scope, call add the scope. We can also define the language code with firebase.auth().languageCode = 'pt';. If we want to send a specific custom parameter with the request, we can call the setCustomParamter() method. Consider this example:

provider.setCustomParameters({
 'login_hint': 'admin'
});

So, once you click on the Login with Google button, it will trigger the popup to authenticate with Google:

So if you are already logged in and try to log in with the same email ID with different providers, it throws errors, as illustrated:

Okay, so now let's see how we can handle these types of errors.