title: Unhandled Promise Rejection is not defined
body: <p>In my React Native App, I have a custom login facebook button :</p>
  
  <pre><code>&lt;Button onPress={() =&gt; this.handleFacebookLogin()}&gt;
    &lt;Text&gt;Login with Face&lt;/Text&gt;
  &lt;/Button&gt;
  </code></pre>
  
  <p>And the handleFacebookLogin function :</p>
  
  <pre><code> handleFacebookLogin () {
       LoginManager.logInWithReadPermissions(['public_profile', 'email', 'user_friends']).then(
         function (result) {
           if (result.isCancelled) {
             console.log('Login cancelled')
           } else {
             console.log('Login success with permissions: ' + result.grantedPermissions.toString())
             AccessToken.getCurrentAccessToken().then(
               (data) =&gt; {
                 signInFacebookLoginInFirebase(data.accessToken)
                 //this.signInFacebookLoginInFirebase(data.accessToken)
               }
             )
           }
         },
         function (error) {
           console.log('Login fail with error: ' + error)
           alert('Error at login, no network ?')
         }
       )
   }
  </code></pre>
  
  <p>But I get this error :</p>
  
  <blockquote>
    <p>Possible Unhandled Promise Rejection (id: 20): ReferenceError:
    signInFacebookLoginInFirebase is not defined
    TypeError: _this2.signInFacebookLoginInFirebase is not a function</p>
  </blockquote>
  
  <p>TypeError: _this2.signInFacebookLoginInFirebase is not a function</p>
  
  <p>And signInFacebookLoginInFirebase method :</p>
  
  <pre><code>   signInFacebookLoginInFirebase(facebookToken){
       const credential = Fb.firebase.auth.FacebookAuthProvider.credential(facebookToken);
       Fb.firebase
         .auth()
         .signInWithCredential(credential)
         .then(() =&gt; alert('Account accepted'))
         .catch((error) =&gt; alert('Account disabled'));
     }
  </code></pre>