AWS cognito: Auto login after registration confirmation - amazon-cognito

Question

I am using the JavaScript SDK of AWS Cognito (http://docs.aws.amazon.com/cognito/latest/developerguide/using-amazon-cognito-user-identity-pools-javascript-examples.html).
When a new user completes registration confirmation, the documentation says the user is now ready to sign in. Is it possible to automatically sign in the user at this time?
For eg., after confirmation when I use the following I get null:
userPool.getCurrentUser();
If this is the intended behavior, are there any ways to sign in the user without explicitly asking the user again?
I know this is not a good idea, one thing I can think of is to save the user credentials in local storage and use them after confirmation to automatically sign in. Any other ideas better than this?

Answer 1

Upon user signup, your backend will be receiving users credentials, which you can use to generate the JWT token. Then you can add the JWT token in the same response, which can be use by the browser client to request authorized endpoints.
Example:
AWSCognito.config.region = 'us-east-1'; //This is required to derive the endpoint
var poolData = {
UserPoolId: 'us-east-1_TcoKGbf7n',
ClientId: '4pe2usejqcdmhi0a25jp4b5sh3'
};
var userPool = new AWSCognito.CognitoIdentityServiceProvider.CognitoUserPool(poolData);
var attributeList = [];
var dataEmail = {
Name: 'email',
Value: 'email#mydomain.com'
};
var authenticationData = {
Username: 'username',
Password: 'password',
};
var attributeEmail = new AWSCognito.CognitoIdentityServiceProvider.CognitoUserAttribute(dataEmail);
attributeList.push(attributeEmail);
userPool.signUp(authenticationData.Username, authenticationData.Password, attributeList, null, function (err, result) {
if (err) {
alert(err);
return;
}
var authenticationDetails = new AWSCognito.CognitoIdentityServiceProvider.AuthenticationDetails(authenticationData);
var userData = {
Username: authenticationData.Username,
Pool: userPool
};
var cognitoUser = new AWSCognito.CognitoIdentityServiceProvider.CognitoUser(userData);
cognitoUser.authenticateUser(authenticationDetails, {
onSuccess: function (result) {
console.log('access token + ' + result.getAccessToken().getJwtToken());
/*Use the idToken for Logins Map when Federating User Pools with Cognito Identity or when passing through an Authorization Header to an API Gateway Authorizer*/
console.log('idToken + ' + result.idToken.jwtToken);
/*Return the result.idToken.jwtToken with the response*/
},
onFailure: function (err) {
alert(err);
},
});
});