Simplest Possible Logging

console.log and console.error is really enough and the world has too many log frameworks. This library should not be used, but if you decide to anyway, you get the following:

• Timestamped log lines in local time zone.
• Log levels: DEBUG, INFO, WARN, ERROR
• Possible to redirect.
• Reasonable defaults.
• Singleton

Defaults

The default log level is INFO. Debug messages are not shown. Info, warnings and errors are.

By default DEBUG and INFO go to console.log (and thus stdout), while WARN and ERROR go to console.error (thus stderr).

*** 1.0.0 - changed to local time zone. Earlier versions times were always in Zulu.

The default time format is ISO8601 in the local time zone.

Install

npm install bog

Example

var log = require('bog');

log.info('Something wonderful has happened Your AMIGA is alive !!!');

Would produce:

2013-06-13 19:05:35.482 INFO Something wonderful has happened Your AMIGA is alive !!!

API

log.debug(args...)

Same as log.info.

log.info(args...)

Outputs logging at the INFO level. args is one or many arguments which is passed to the output function.

Example

log.info('and, even', 'better...');

Outputs

2013-06-13 19:05:35.482 INFO and even better...

N.b. The above is conceptually the same as

console.log((new Date()).toISOString(), 'INFO', 'and, even', 'better...');

log.warn(args...)

Same as log.info, but to stderr.

log.error(args...)

Same as log.info, but to stderr.

log.level(level)

Sets the lowest reported log level, for example warn would enable warn and error, and disable debug and info.

Example:

log.level('warn');

log.redirect(out, err)

out is the output function for DEBUG and INFO and err is the output function for WARN and ERROR. null is appropriate to turn off output.

Example:

log.redirect(null, null); // silences all logging
...
log.redirect(console.log, console.error); // reinstates defaults

log.callback()

Set a callback function for each log message. The callback will receive an object like this:

{
  "timestamp": 1462947947643,
  "datetime" : "2016-05-11 8:25:47",
  "level"    : "INFO",
  "args"     : ["This is the", "arguments array"]
}

log.config()

Spills the beans of the internal config. Can be used to alter the formatting.

Example (deprecated)

This formatting is deprecated, do not use.

log.config().format = function(level, args) {
    if (level === 'info') {
        args.unshift('Prepended');
        args.push('Appended');
    }
    return args;
};

Enable ISO8601 time designator 'T' and timezone

*** Since 1.0.0

It's possible to turn on the time designator and timezone.

log.config().includeTimeDesignator = true;
log.config().includeTimeZone = true;

log.info('Something wonderful has happened Your AMIGA is alive !!!');

If machine timezone is India this would produce:

2013-06-13T19:05:35.482+0530 INFO Something wonderful has happened Your AMIGA is alive !!!

Notice that zulu (GMT) time is denoted by a 'Z'.

License

MIT License (MIT).