Node Cookbook - Third Edition

How it works...

In our recipe, we initially set DEBUG to *, which means enable all logs. Then we wanted to zoom in explicitly on express related log messages. So we set DEBUG to express:*, which means enable all logs that begin with express:. By convention, modules and frameworks delimit sub-namespaces with a : (colon).

At an internal level, the debug module reads from the process.env.DEBUG, splits the string by whitespace or commas, and then converts each item into a regular expression.

When a module uses the debug module, it will require debug and call it with a namespace representing that module to create a logging function that it then uses to output messages when debug logs are enabled for that namespace.

Using the debug moduleFor more ...