Ionic 2 Facebook login
<p>I found this code:</p>

<pre><code>login() {
    this.platform.ready().then(() =&gt; {
        this.facebookLogin().then((success) =&gt; {
            alert(success.access_token);
        }, (error) =&gt; {
            alert(error);
        });
    });
}


facebookLogin() {
    return new Promise(function(resolve, reject) {
        var browserRef = window.cordova.InAppBrowser.open("https://www.facebook.com/v2.0/dialog/oauth?client_id=" + "CLIENT_ID_HERE" + "&amp;redirect_uri=http://localhost/callback&amp;response_type=token&amp;scope=email", "_blank", "location=no,clearsessioncache=yes,clearcache=yes");
        browserRef.addEventListener("loadstart", (event) =&gt; {
            if ((event.url).indexOf("http://localhost/callback") === 0) {
                browserRef.removeEventListener("exit", (event) =&gt; {});
                browserRef.close();
                var responseParameters = ((event.url).split("#")[1]).split("&amp;");
                var parsedResponse = {};
                for (var i = 0; i &lt; responseParameters.length; i++) {
                    parsedResponse[responseParameters[i].split("=")[0]] = responseParameters[i].split("=")[1];
                }
                if (parsedResponse["access_token"] !== undefined &amp;&amp; parsedResponse["access_token"] !== null) {
                    resolve(parsedResponse);
                } else {
                    reject("Problem authenticating with Facebook");
                }
            }
        });
        browserRef.addEventListener("exit", function(event) {
            reject("The Facebook sign in flow was canceled");
        });
    });
}
</code></pre>

<p>I am a bit confused, how does Ionic 2 app recognizes when user is signed in with some social apps like facebook/google?
For example, I want to make a landing page, which prompts for facebook login, and as soon as user is logged-in, dont show the page.
I am familiar with nodejs+passportjs which stores session/cookies, but how Ionic 2 it does?</p>