pseudo.js

export default (authenticate, deny) => {
    // from https://developers.facebook.com/docs/reference/javascript/FB.login/v6.0
    FB.login(function(response) {
        if (response.authResponse) {
            console.log('Welcome!  Fetching your information.... ');

            FB.api('/me', function(response) {
                console.log('Good to see you, ' + response.name + '.');

                // actual integration
                authenticate(response);
            });
        } else {
            console.log('User cancelled login or did not fully authorize.');

            deny();
        }
    });
}