Hub

Overview

Hub is a lightweight and opinionated logging utility plus a spiritual successor to debug-js. It simplifies logging by ( potentially) wrapping the console object and supports multiple logging levels.

Use

You use the DEBUG environment variable, just as you would with debug-js. The other levels (i.e. INFO, WARN, ERROR and OFF) are also available.

Simplest use from command line:

DEBUG="pkg1,pkg3/sub*" WARN="pkg2*" node app.js

Which will set the pkg1 and all logs namespaces starting with pkg3/sub namespaces to debug level and all namespaces starting with pkg2 to warn level. Each environment variable is a comma separated list of globs. Default level is always info.

Motivation

We have a perfectly good logger in [console](mdn link), however, we do not use it because the standard forgot to add a way to set the level. So console.debug is useless, as it is equivalent to console.log. Hub changes that by retrofitting the debug, info, warn and error methods in console (and not touching anything else).

It also adds a filename, colors and time since the last invocation to the log. All these are features also found in debug.

You can use the console object throughout the code and then add a namespace that matches a base path (or let Hub autodiscover it based on the deno.json file), which performs the magic of retrofitting the console object and making it a namespaced log. You can, of course, use "logs" throughout your code without touch the native console object.

Examples

Simple Logging

Create a logger instance for a specific namespace:

const log = hub("pkg"); // Without any enviroment variable, level is 'info'

// Log at different levels
log.info("This is an info message");
log.debug("This is a debug message"); // Will not print
log.error("Something went wrong");

// Change log level
log.level = "debug";
log.debug("This is a debug message"); // This one will print!

Turn off completely

Sometimes you do not want to see logs, you can set the off level as:

OFF="*" WARN="pkg2*" node app.js

Note that the OFF level will have priority as it is higher.

Set namespaces

If you want to set a namespace for an entire package (or sub-directory) you can do:

hub("pkg", { root: import.meta.dirname });

The previous will make sure that all files under that root share the same namespace.

Features

• Logging Level: sets logging levels for console
• Filename and Line: how many times have you forgotten where you added that printout statement?
• Namespace: either manual or automatic (in Deno) namespace per module
• Control via Environment: useful to turn on/off in different environments
• Time: prints time taken between printouts
• Color: per namespace/log, useful for debugging

Wny not X?

• Console: lack of levels
• Consola: does not do filename and clean namespaces
• pino: large dependency tree, commitment to structure

Contributing

1. Fork the repository.
2. Create a feature branch (git checkout -b feature-branch).
3. Commit your changes (git commit -m "Added a new feature").
4. Push the branch (git push origin feature-branch).
5. Open a Pull Request.

License

This project is open-source and available under the MIT License.