ANSI Logger for Node.js

Console logger with support for colors and log levels, it complies to the default console.log interface, with methods like log,error,warn and debug but is extended with some extra levels for nice formatting purposes.

API

setOptions(options:Object) : void

Set options changes the internal setting of the logger and the behavior will change after this call. if you change the log levels to output the new mask of log levels is outputted to the INFO level, so if INFO level isn't in the new log level mask, nothing will be outputted.

error(msg1 [, msg2,..]) : msg1

Log to the error level, iff the ERROR mask is present in the log level mask of the logger the message(s) will be outputted and formatted as an error.

warn(msg1 [, msg2,..]) : msg1

Log to the warn level, iff the WARN mask is present in the log level mask of the logger the message(s) will be outputted and formatted as an error.

success(msg1 [, msg2,..]) : msg1

Log to the success level, iff the SUCCESS mask is present in the log level mask of the logger the message(s) will be outputted and formatted as an error.

log(msg1 [, msg2,..]) : msg1

Log to the log level, iff the LOG mask is present in the log level mask of the logger the message(s) will be outputted and formatted as an error.

default(msg1 [, msg2,..]) : msg1

Alias for log

info(msg1 [, msg2,..]) : msg1

Log to the info level, iff the INFO mask is present in the log level mask of the logger the message(s) will be outputted and formatted as an error.

debug(msg1 [, msg2,..]) : msg1

Log to the debug level, iff the DEBUG mask is present in the log level mask of the logger the message(s) will be outputted and formatted as an error.

verbose(msg1 [, msg2,..]) : msg1

Log to the verbose level, iff the VERBOSE mask is present in the log level mask of the logger the message(s) will be outputted and formatted as an error.

title(msg, [, msg2,..]) : msg1

Title is a special level, it is outputted to level LOG, but formatted differently.

colorize(msg, color, style) : String

Adds ANSI color characters to the message, and return the result. NB! if the no-color option is set, the message is returned without adding the ANSI color characters.

print(msg, [loglevel, color, style]) : void

Output to stdout or stderr if the loglevel is ERROR

formatTime([time]) : String

Format time and return the colored and formatted string.

formatLogLevel(loglevel, msg) : String

Add the colors of the loglevel to the message.

formatGroup() : String

Format the group if such is configured.

resolveLogLevel(loglevel) : String

Get the string representation of the log level mask.

formatTypes(msg, [padding = 0, depth = 3]) : String

Recursively format msg. It is nice to format Object and arrays with. You can set depth in order to avoid infinite recursion.

formatError(err) : String

Formats an error, you can use e.g. in a try/catch block pass the error to formatError and it will output it to ERROR log level.

Log level system

The log level system is based on bit masks, with pre-compiled set of log levels.

Level masks

ERROR:    0b0000001
WARN:     0b0000010
SUCCESS:  0b0000100
LOG:      0b0001000
INFO:     0b0010000
DEBUG:    0b0100000
VERBOSE:  0b1000000

This way it's easy to compile a custom level mask, all you have to do is bit-wise or the masks together for the levels you want in your output.

E.g. if we only want ERROR and INFO outputted:

var logLevel = AnsiLogger.prototype.ERROR | AnsiLogger.prototype.INFO;
var logger = new AnsiLogger({'log-level': logLevel});
logger.error('test');
logger.warn('test');
logger.success('test');
logger.log('test');
logger.info('test');
logger.debug('test');
logger.verbose('test');

Output:

[17:41:26.052] [ERROR] test
[17:41:50.807] [INFO]  test

Pre-compiled log level masks

ERROR_LEVEL
WARN_LEVEL
SUCCESS_LEVEL
LOG_LEVEL
INFO_LEVEL
DEBUG_LEVEL
VERBOSE_LEVEL

Each of the levels listed above will output their own level and them above. So LOG_LEVEL will output ERROR,WARN,INFO and LOG.

Options

log-level, default: LOG_LEVEL

Sets the log level of the logger. NB! if the default log level is used, no [level] indication is outputted, this will behavior will be optional in a later release.

no-colors, default: false

Disables the colors. It can be nice if you will redirect the output to a file.

colors

Setting the colors of the different log-levels. Each color is function that takes a string and return the string with the ANSI characters added.

var clc = require('cli-color')
var AnsiLogger = require('ansi-logger');
var logger = new AnsiLogger({
  'colors': {
    'error': clc.bgMagenta
  }
});

group, default: null

Sets up a group for the logger:

var logger = new AnsiLogger({'group': 'server', 'group-color': 'blue'});
logger.log('test');

Outputs:

[17:44:35.443] [server] test

group-color, default: null

Sets the color for the group. The color strings comes from the cli-color npm module

Build

For building a new version simply run. NB! It is required that coffee-script is globally installed.

coffee -cbo lib lib/src