winston

[winston] is designed to be a simple and universal logging library with support for multiple transports. A transport is essentially a storage device for your logs. Each winston logger can have multiple transports (see: Transports) configured at different levels (see: Logging levels). For example, one may want error logs to be stored in a persistent remote location (like a database), but all logs output to the console or a local file.

koa

[koa] is a new web framework designed by the team behind Express, which aims to be a smaller, more expressive, and more robust foundation for web applications and APIs. By leveraging async functions, Koa allows you to ditch callbacks and greatly increase error-handling. Koa does not bundle any middleware within its core, and it provides an elegant suite of methods that make writing servers fast and enjoyable.