title: Is there any method like "silent login" for facebook plugin of ionic?
body: <p>Google+ plugin for ionic provides a method <code>silentLogin()</code> using this method you can check if they're already signed in to the app and sign them in silently (without asking user to sign in or without showing any dialog) if they are logged in.</p>
  
  <p>Now, My question is, is there any method for facebook plugin too?
  If yes,please provide information of how to achieve it ?</p>
  
  <p>If no, then please tell me alternative ways of doing it.</p>
  
  <p><strong>What I want to do is</strong> check if user has previously loggedin using facebook in my app, and he has not logged out. then next time if user is already logged in  perform log in silently (without needing user's interaction or showing any dialog) and move to the next page. and if user is not logged in already then do nothing.</p>
  
  <p>I have achieved <code>silentLogin()</code> for google plus in following way.</p>
  
  <pre><code>constructor(public navCtrl: NavController, public platform: Platform,
  public navParams: NavParams, private sanitizer: DomSanitizer,
  private googlePlus: GooglePlus, private fb: Facebook, private sqlite: SQLite) {
  
      platform.ready().then(() =&gt; {
        this.googlePlus.trySilentLogin({})
          .then(res =&gt; {
            this.loginGPlusSuccess(res);
          }).catch(e =&gt; console.log("failed login silenty"));
      }).catch(e =&gt; console.log("platform is not ready", e));
  
    }
  </code></pre>
  
  <p>for Facebook, I have done login in following way,</p>
  
  <pre><code>loginFb() {
      this.fb.login(['public_profile', 'user_friends', 'email'])
        .then(res =&gt; {
          if (res.status === "connected") {
            this.isLoggedIn = true;
            this.getFbUserDetail(res.authResponse.userID);
            this.saveData();
            this.navigateToHome();
          } else {
            this.isLoggedIn = false;
          }
        })
        .catch(e =&gt; console.log('Error logging into Facebook', e));
    }
  </code></pre>