Question: With the use case 4

[tastafur]

This code is a sample, but it would not really be used within cognitoUser.authenticateUser because the credentials were just created with new AWS.CognitoIdentityCredentials, it would not be necessary to refresh them, it is a code the .refresh method to say that this method exists, no?

AWS.config.credentials.refresh((error) => {
  if (error) {
      console.error(error);
  } else {
       // Instantiate aws sdk service objects now that the credentials have been updated.
       // example: var s3 = new AWS.S3();
       console.log('Successfully logged!');
  }
});