Log4js for Node.js

Log4js is a comprehensive and configurable logging framework for Node.js, currently stable at version 6.9.1. It provides various appenders for outputting logs to the console, files (with rolling), and network services, alongside flexible layout patterns and category-based logging. While sharing a name with Java's Log4j, it behaves distinctly, making direct assumptions about parity a source of confusion. The project is actively maintained, with regular updates and a dedicated community. Key differentiators include its extensive appender support (many as optional, separate packages), highly customizable log levels (TRACE, DEBUG, INFO, WARN, ERROR, FATAL), and built-in TypeScript definitions, offering a robust solution for managing application logs in various environments.