Middy
The stylish Node.js middleware engine for AWS Lambda
...A middleware engine allows you to focus on the strict business logic of your Lambda and then attach additional common elements like authentication, authorization, validation, serialization, etc. in a modular and reusable way by decorating the main business logic. One of the main strengths of serverless and AWS Lambda is that, from a developer perspective, your focus is mostly shifted toward implementing business logic. Anyway, when you are writing a handler, you still have to deal with some common technical concerns outside business logic, like input parsing and validation, output serialization, error handling, etc.