text: // Copyright 2010-2019 Amazon.com, Inc. or its affiliates. All Rights Reserved.
  // 
  // This file is licensed under the Apache License, Version 2.0 (the "License").
  // You may not use this file except in compliance with the License. A copy of
  // the License is located at
  // 
  // http://aws.amazon.com/apache2.0/
  // 
  // This file is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR
  // CONDITIONS OF ANY KIND, either express or implied. See the License for the
  // specific language governing permissions and limitations under the License.
  
  // snippet-sourcedescription:[This post authentication sample Lambda function sends data from a successful sign-in to CloudWatch Logs.]
  // snippet-service:[cognito-idp]
  // snippet-keyword:[JavaScript]
  // snippet-sourcesyntax:[javascript]
  // snippet-keyword:[Amazon Cognito]
  // snippet-keyword:[Code Sample]
  // snippet-keyword:[lambda_trigger]
  // snippet-sourcetype:[full-example]
  // snippet-sourcedate:[2019-01-30]
  // snippet-sourceauthor:[AWS]
  
  // snippet-start:[cognito.javascript.lambda-trigger.post-authentication]
  exports.handler = (event, context, callback) => {
  
      // Send post authentication data to Cloudwatch logs
      console.log ("Authentication successful");
      console.log ("Trigger function =", event.triggerSource);
      console.log ("User pool = ", event.userPoolId);
      console.log ("App client ID = ", event.callerContext.clientId);
      console.log ("User ID = ", event.userName);
  
      // Return to Amazon Cognito
      callback(null, event);
  };
  // snippet-end:[cognito.javascript.lambda-trigger.post-authentication]