@lambda-lambda-lambda/router

L³ router

AWS CloudFront Lambda@Edge serverless application router.

Features

• Request/Response handling API.
• Routes and URI Resource support.
• Local/Globally scoped Middleware.
• Visual Studio Code integration.
• Open Source, MIT licensed, FREE.
• Lightweight (no dependencies).

How does it work?

In its most basic form the library provides helper methods that translate the CloudFront Lambda@Edge origin-request allowing you to handle response processing without the need to construct complex Lambda dependent responses.

To better visualize how L³ fits in the current AWS ecosystem the following high-level graph describes the HTTP Request/Response lifecycle and role of each AWS provided service.

Getting started

The easiest way to created an application, without the need to manually install this package, is to use the L³ Visual Studio Code extension. Doing so allows you to..

• Scaffold app sources and dependencies.
• Run it locally (in Remote - Containers)
• Test code changes in realtime.
• Deploy app sources to AWS.
• Generate JSDoc/Swagger documentation.

Build dependencies

If you're not using the L³ VS Code extension and want to run this package locally you must install the following dependencies:

• AWS SAM CLI
• Node.js

Manual installation

If you just looking to leverage the Request/Response handling API in your Lambda functions, install this package using NPM.

$ npm install @lambda-lambda-lambda/router

Documentation

• Introduction
• Getting Started
• AWS requirements
• Running your App
• Usage
• Common methods
• Complex routing
• Middleware
• Developers
• Testing

AWS changes starting in Node.js 24 (CloudWatch warning)

Going forward, it is recommended that you build your L³ application using async handlers in anticipation of the AWS changes below.

AWS Lambda plans to remove support for callback-based function handlers starting with Node.js 24. You will need to update this function to use an async handler to use Node.js 24 or later. For more information and to provide feedback on this change, see aws/aws-lambda-nodejs-runtime-interface-client#137

While backwards compatibity will be supported for older Node.js releases this support will eventually be phased out with the deprecation of nodejs22.x (Apr 30, 2027).

See AWS Node.js Supported Runtimes for support information.

Versioning

This package is maintained under the Semantic Versioning guidelines.

License and Warranty

This package is distributed in the hope that it will be useful, but without any warranty; without even the implied warranty of merchantability or fitness for a particular purpose.

lambda-lambda-lambda/router is provided under the terms of the MIT license

AWS is a registered trademark of Amazon Web Services, Inc.

Author

Marc S. Brooks