title: How to logout from all providers in AWS Cognito?
body: <p>I use AWS Cognito authentication in my web application. Users can authenticate using one of the three identity providers: cognito user pool (by username and password), facebook and google.
  Here is how I get credentials:</p>
  
  <pre><code>AWS.config.credentials = new AWS.CognitoIdentityCredentials({
      IdentityPoolId: identityPoolId,
      Logins: logins
  });
  AWS.config.credentials.get(err =&gt; {
      console.log("Amazon Cognito Identity", 
      AWS.config.credentials.identityId);
  });
  </code></pre>
  
  <p>logins - Object, that can contain tokens from cognito, facebook and google.</p>
  
  <p>What should web application does if user click logout button?
  I could do <code>userPool.getCurrentUser().signOut()</code> if current user is exists (current user is exists only in cognito username, password authentication)
  But what should I do if somebody signs in using facebook or google? </p>