Bunyan is a simple and fast JSON logging library for Node.js applications. It provides a structured and customizable logging solution, allowing you to easily log events, errors, and other information in a structured format. Bunyan logs are written in JSON format, making them easy to parse and analyze.
log4js is a flexible and feature-rich logging library for Node.js applications. It provides a simple and intuitive API for logging messages to various output targets, such as the console, files, databases, and more. log4js supports different log levels, allowing you to control the verbosity of your logs and filter them based on severity.
Both Bunyan and Log4js are popular logging libraries in the Node.js ecosystem. Bunyan has been around for longer and has a larger user base, but Log4js has also gained popularity and has a growing community.
Bunyan and Log4js offer similar core logging functionalities such as log levels, log formatting, and log output to various destinations. However, Bunyan is known for its simple and straightforward API, while Log4js provides more advanced features like loggers hierarchy, log rolling, and log filtering.
Both libraries are designed to be performant, but Bunyan is known for its high-performance logging capabilities. It is optimized for speed and has minimal overhead, making it suitable for high-throughput applications. Log4js also performs well, but it may have slightly higher overhead due to its additional features.
Bunyan is primarily designed for Node.js applications and integrates well with other Node.js libraries and frameworks. It provides built-in support for logging in JSON format, which is commonly used in Node.js environments. Log4js, on the other hand, is more versatile and can be used in both Node.js and browser environments, making it suitable for full-stack applications.
Community and Maintenance
Both Bunyan and Log4js have active communities and are actively maintained. However, Bunyan has a larger community and a longer history of development, which may provide more stability and support. Log4js, although newer, has been gaining popularity and has regular updates and bug fixes.