Set logLevel to 'NONE' in your App to disable all logging.
The service/app is going to stop or become unusable soon.
Service/App in critical condition, an operator should look into it.
Error in particular request/operation, but the service continues servicing other requests.
Something looks fishy, like an operation taking too long or having too few/many results, but system still functional.
Something noticeable happened that is perhaps useful or imperative to know about.
Some operation finished and was OK, we might care about that.
Some extraneous info about some operation, eg operation finished
Extra, casual logging we almost shouldn't care about
Verbose logging that should be looked at rarely / when we have issues
Only for debugging, like entering and leaving some function / subsystem with input and results. The debugLevel can further control the granularity. If logLevel ends up as undefined in effective options, debug is the implicit default.
Prints the call stack when printing, similar to console.trace. Use traceLevel in effect to control its granularity.
Temporary silly / development only messages, so they can easily be found & removed
Enum holds all logLevels as lowercase string, eg 'fatal', 'critical' etc. and the corresponding numeric value.
See
LogLevel - Choosing What Severity To Print