cognito_to_auth0_custom_login_using_aws_sdk.js

function login(email, password, callback) {
  const AWS = require('aws-sdk@2.1.31');
  global.fetch = require('node-fetch');
  const AmazonCognitoIdentity = require('amazon-cognito-identity-js@3.0.14');
  
  const authenticationData = {
    Username: email,
    Password: password,
  };
  const authenticationDetails = new AmazonCognitoIdentity.AuthenticationDetails(
    authenticationData
  );
  const poolData = {
    UserPoolId : configuration.userPoolId,
      ClientId : configuration.clientId
  };
  const userPool = new AmazonCognitoIdentity.CognitoUserPool(poolData);
  const userData = {
    Username: email,
    Pool: userPool,
  };

  const cognitoUser = new AmazonCognitoIdentity.CognitoUser(userData);
  
  cognitoUser.authenticateUser(authenticationDetails, {
    onSuccess(result){
      const token = result.idToken.jwtToken;

      const pem = configuration.PEM.replace(/\\n/g, '\n');
      jwt.verify(token, pem, { algorithms: ['RS256'] }, function(err, decodedToken) {
          if(err !== null){
          console.error(err);
        }else{
          if(decodedToken.aud !== configuration.clientId) {
            console.error(err);
            return callback(err);
          }

          if(decodedToken.iss !== `https://cognito-idp.ap-northeast-1.amazonaws.com/${configuration.userPoolId}`) {
            console.error(err);
            return callback(err);
          }

          const nowTime = Math.floor(new Date().getTime() / 1000);
          if(nowTime > decodedToken.exp) {
            console.error(err);
            return callback(err);
          }
					callback(null, {
            //username: email, // Requires UsernameがONの時はいる
            user_id: decodedToken.sub,
            email: decodedToken.email
          });
        }
      });
    },
    onFailure(err){
        console.error(err);
    },
  });
 
}