AWS Lambda Custom OAuth2

Question

I am trying to implement OAuth2 in a react-node serverless application. Similar to https://serverless-stack.com and OAuth2 above it.

I have followed AWS nodejs blueprint and confused with OAuth provider part.

https://github.com/awslabs/aws-apigateway-lambda-authorizer-blueprints/tree/master/blueprints/nodejs

(Here I need to achieve 20th line '// 1. Call out to OAuth provider')

I have also tried following articles/repos and could not achieve my requirements.

https://github.com/kennu/serverless-cognito-oauth2

http://www.awsomeblog.com/api-gateway-custom-authorization/

http://docs.aws.amazon.com/apigateway/latest/developerguide/use-custom-authorizer.html

How to set up an OAuth2 Authentication Provider with AWS API Gateway?

https://github.com/laardee/serverless-authentication-boilerplate

https://serverless.com/framework/docs/providers/aws/events/apigateway/#http-endpoints-with-custom-authorizers

https://blogs.edwardwilde.com/2017/01/12/creating-an-oauth2-custom-lamda-authorizer-for-use-with-amazons-aws-api-gateway-using-hydra/

https://github.com/matthoiland/serverless-oauth2

https://github.com/mcguinness/node-lambda-oauth2-jwt-authorizer

https://github.com/Serverless-Vienna/Comments-Showcase

My idea of OAuth2 authentication/ authorization is similar to https://babelouest.github.io/glewlwyd/

I used Cognito for Authentication and trying to use OAuth2 in lambda custom Auth for Authorization.

Please let me know of any article or way to achieve custom authorization of AWS API Gateway endpoints using OAuth2.